Program slicing has been proven to be an effective approach to aid program understanding in recent years. A dynamic program slicer computes the set of instructions that may have affected or been affected by the given variable in certain location of the instruction stream. In this paper, we implement a dynamic forward slicer SPS which can extract the part of the code which is influenced by the user, and organize our result with the call graph of the program. Our experiments show that SPS has not only achieved high efficiency, but also provides clearer slicing results than traditional methods.