Many optimization methods are used to raise the quality of target code in the process of compiling.Because some optimization methods for compiling are too complicated

hidden dangers won't be avoided for reliability and security of compiling.The existing defects of compiler are usually caused at the optimization phase.Mostly traditional correctness of compiling optimization only focus on correctness of optimization algorithm

but only when the algorithm is implemented correctly

the optimization process run in practice can be proved to be correct.This paper proposes a method based on simulation relation to verify correctness of compiling optimization realization.We build up simulation relation between code before optimization and code after optimization to generate logic condition that the correctness optimization should satisfy

and then we verify it if logic condition is satisfied or not to judge if compiling optimization realization is correct or not after each optimization is finished.The method is proved to be effective and reliable by verifying statement exchange and variable substitution in the process of optimization compiling.