German cache coherence protocol is used in parallel multi-processor systems, and the verification of German protocol has always been a hot spot in international industry and academia. We generate the flow chart of German protocol and describe each step of the flow chart. Besides, we present a method to verify the cache coherence protocol by flow analysis and inductive invariants in this paper. By searching for the relations between the invariants and the flow chart of German protocol, we can further analyze and verify the correctness of German protocol.