In this paper, we will analyze the coupled model induced bias of the East African rainfall annual cycle by comparing the historical and AMIP simulations for each model, with particular emphasis on the MRI-CGCM3 model, which best simulates the East African rainfall annual cycle  in the AMIP run but has a coupled model bias typical of the multimodel mean. The  paper is organized as: Section \ref{sec:data} describes the data  and models used in this study as well as some special treatment of calculations; Section \ref{sec:multimodel} show the historical$-$AMIP bias from multimodel statistics and individual models; detailed analysis of the MRI-CGCM3 is in Sections \ref{sec:mri}; the main conclusions of the paper and associated discussion are provided in Section \ref{sec:conclusion}.