Summary: In this paper, the error analysis of finite element method for solving Cahn-Hilliard-Brinkman equation with variable coefficients is studied. The energy convex splitting method is used in the time scheme, and the mixed finite element method is used in the space scheme to discretize. It is proved that the full discrete scheme is energy attenuated. In error analysis, the term containing concentration and Peclet number is decomposed into two terms by using Cauchy mean value theorem. The results show that the proposed scheme is second-order accuracy in time.