The application of program transformation method to logic program is mainly based on such theory, namely, Fold / Unfold transformation holds the least Herbrand model semantics and the semantics of answer substitution set of logic program. 程序变换方法在逻辑程序中的应用主要是基于这样的理论结果,即Fold/Unfold变换保持了逻辑程序的最小Herbrand模型语义和答复置换集语义。