diff --git a/src/main/java/abstractSyntaxTree/Expression/BinaryExpression.java b/src/main/java/abstractSyntaxTree/Expression/BinaryExpression.java
index 72af1be..8ddd6bf 100644
--- a/src/main/java/abstractSyntaxTree/Expression/BinaryExpression.java
+++ b/src/main/java/abstractSyntaxTree/Expression/BinaryExpression.java
@@ -14,6 +14,12 @@ public class BinaryExpression extends AbstractType implements IExpression{
     public IExpression left;
     public IExpression right;
 
+    public BinaryExpression(String operator, IExpression left, IExpression right) {
+        this.operator = operator;
+        this.left = left;
+        this.right = right;
+    }
+
     @Override
     public TypeCheckResult typeCheck() throws Exception {
         TypeCheckHelper helper = new TypeCheckHelper();
diff --git a/src/main/java/abstractSyntaxTree/Expression/IExpression.java b/src/main/java/abstractSyntaxTree/Expression/IExpression.java
index a679711..f4cdf75 100644
--- a/src/main/java/abstractSyntaxTree/Expression/IExpression.java
+++ b/src/main/java/abstractSyntaxTree/Expression/IExpression.java
@@ -1,9 +1,10 @@
 package abstractSyntaxTree.Expression;
 
 import TypeCheck.TypeCheckResult;
+import abstractSyntaxTree.Node;
 import org.objectweb.asm.MethodVisitor;
 
-public interface IExpression {
+public interface IExpression extends Node {
     // typeCheck method
     TypeCheckResult typeCheck() throws Exception;
 
diff --git a/src/main/java/astGenerator/ASTGenerator.java b/src/main/java/astGenerator/ASTGenerator.java
index 24e582f..c31af91 100644
--- a/src/main/java/astGenerator/ASTGenerator.java
+++ b/src/main/java/astGenerator/ASTGenerator.java
@@ -4,6 +4,7 @@ import abstractSyntaxTree.Class.FieldDecl;
 import abstractSyntaxTree.Class.MethodDecl;
 import abstractSyntaxTree.Class.RefType;
 import abstractSyntaxTree.Expression.BinaryExpression;
+import abstractSyntaxTree.Expression.IExpression;
 import abstractSyntaxTree.Node;
 import abstractSyntaxTree.Parameter.Parameter;
 import abstractSyntaxTree.Parameter.ParameterList;
@@ -114,7 +115,8 @@ public class ASTGenerator extends DecafBaseVisitor<Node> {
 
     @Override
     public Node visitReturnStmt(DecafParser.ReturnStmtContext ctx) {
-        return new ReturnStatement(new BinaryExpression());
+        Node expression = visitExpression(ctx.expression());
+        return new ReturnStatement((IExpression) expression);
     }
 
     @Override
@@ -132,22 +134,25 @@ public class ASTGenerator extends DecafBaseVisitor<Node> {
         if (ctx.elseStmt() != null) {
             return visitIfStmt(ctx.ifStmt());
         } else {
+            Node expression = visitExpression(ctx.ifStmt().expression());
             Node ifStatement = visitStatement(ctx.ifStmt().statement());
             Node elseStatement = visitStatement(ctx.elseStmt().statement());
-            return new IfElseStatement(new BinaryExpression(), (IStatement) ifStatement, (IStatement) elseStatement);
+            return new IfElseStatement((IExpression) expression, (IStatement) ifStatement, (IStatement) elseStatement);
         }
     }
 
     @Override
     public Node visitIfStmt(DecafParser.IfStmtContext ctx) {
+        Node expression = visitExpression(ctx.expression());
         Node statement = visitStatement(ctx.statement());
-        return new IfStatement(new BinaryExpression(), (IStatement) statement);
+        return new IfStatement((IExpression) expression, (IStatement) statement);
     }
 
     @Override
     public Node visitWhileStmt(DecafParser.WhileStmtContext ctx) {
+        Node expression = visitExpression(ctx.expression());
         Node statement = visitStatement(ctx.statement());
-        return new WhileStatement(new BinaryExpression(), (IStatement) statement);
+        return new WhileStatement((IExpression) expression, (IStatement) statement);
     }
 
     @Override
@@ -167,7 +172,6 @@ public class ASTGenerator extends DecafBaseVisitor<Node> {
     return null;
     }
 
-
     @Override
     public Node visitAssign(DecafParser.AssignContext ctx) {
         return new AssignStatementExpression();
@@ -182,4 +186,79 @@ public class ASTGenerator extends DecafBaseVisitor<Node> {
     public Node visitNewDecl(DecafParser.NewDeclContext ctx) {
         return super.visitNewDecl(ctx);
     }
+
+    @Override
+    public Node visitExpression(DecafParser.ExpressionContext ctx) {
+        if (ctx.subExpression() != null) {
+
+        } else if (ctx.binaryExpr() != null) {
+            return visitBinaryExpr(ctx.binaryExpr());
+        }
+        return null;
+    }
+
+    @Override
+    public Node visitBinaryExpr(DecafParser.BinaryExprContext ctx) {
+        if (ctx.calcExpr() != null) {
+            return visitCalcExpr(ctx.calcExpr());
+        } else if (ctx.nonCalcExpr() != null) {
+            return visitNonCalcExpr(ctx.nonCalcExpr());
+        } else if (ctx.value() != null) {
+            //todo
+        } else if (ctx.binaryExpr() != null) {
+            //todo
+        }
+        return null;
+    }
+
+    @Override
+    public Node visitCalcExpr(DecafParser.CalcExprContext ctx) {
+        if (ctx.calcExpr() != null) {
+            Node left = visitCalcExpr(ctx.calcExpr());
+            Node right = visitDotExpr(ctx.dotExpr());
+            return new BinaryExpression(ctx.LineOperator().getText(), (IExpression) left, (IExpression) right);
+        } else {
+            visitDotExpr(ctx.dotExpr());
+        }
+        return null;
+    }
+
+    @Override
+    public Node visitDotExpr(DecafParser.DotExprContext ctx) {
+        if (ctx.dotExpr() != null) {
+            Node left = visitDotExpr(ctx.dotExpr());
+            Node right = visitDotSubExpr(ctx.dotSubExpr());
+            return new BinaryExpression(ctx.DotOperator().getText(), (IExpression) left, (IExpression) right);
+        } else {
+            visitDotSubExpr(ctx.dotSubExpr());
+        }
+        return null;
+    }
+
+    //todo
+    @Override
+    public Node visitDotSubExpr(DecafParser.DotSubExprContext ctx) {
+        return super.visitDotSubExpr(ctx);
+    }
+
+    @Override
+    public Node visitNonCalcExpr(DecafParser.NonCalcExprContext ctx) {
+        String operator;
+        if(ctx.nonCalcOperator().LogicalOpertor() != null) {
+            operator = ctx.nonCalcOperator().LogicalOpertor().getText();
+        } else {
+            operator = ctx.nonCalcOperator().ComparisonOperator().getText();
+        }
+        Node left = visitSubExpression(ctx.subExpression());
+        Node right = visitExpression(ctx.expression());
+        return new BinaryExpression(operator, (IExpression) left, (IExpression) right);
+    }
+
+    @Override
+    public Node visitSubExpression(DecafParser.SubExpressionContext ctx) {
+        if (ctx.subExpression() != null) {
+            visitSubExpression(ctx.subExpression());
+        }
+        return null;
+    }
 }