Solving commercial bribe problem has been considered as the key anti-corruption task in china. And the commercial bribe in engineer construction is the first one of the six key fields. In this paper, we firstly analyze the features and forms of commercial bribe in engineering construction. Then we analyze this problem based on game theory in detail. We found an analysis frame in Tripartite, which are principle, agent and relative. We firstly make the analyses in three aspects solely and then make a dynamic compound analysis with the tripartite together. Related conclusions are made after each analysis. Based on these conclusions, At last we propose some countermeasures to commercial bribe in engineering construction mainly from mechanism aspects.