diff --git a/src/SysYIRGenerator.cpp b/src/SysYIRGenerator.cpp
index fd689ca..7ddee8e 100644
--- a/src/SysYIRGenerator.cpp
+++ b/src/SysYIRGenerator.cpp
@@ -623,7 +623,7 @@ std::any SysYIRGenerator::visitMulExp(SysYParser::MulExpContext *ctx) {
     cout << "unaryExp().size() > 1\n";
     for(size_t i = 1; i < ctx->unaryExp().size(); i++){
       Value* rhs = any_cast<Value *>(ctx->unaryExp(i)->accept(this));
-      auto opNode = dynamic_cast<antlr4::tree::TerminalNode *>(ctx->children[2 * i + 1]);
+      auto opNode = dynamic_cast<antlr4::tree::TerminalNode *>(ctx->children[2 * i - 1]);
       
       if(opNode->getText() == "*"){
         res = builder.createMulInst(lhs, rhs, lhs->getName() + "*" + rhs->getName());