With the development of wireless communication, MIMO has become a hot research in the field of wireless communication. The prediction of the distribution of field and the channel capacity is the basic of communication system network planning and management which has important significance of the wireless network optimization. In this paper, we select the raytracing model and the mirror image method to establish indoor MIMO channel model and use the Matlab software to simulate the model. Firstly, we should establish the specific indoor scene and predict the path loss. By the comparison of the predicted and measured values, we can verify the correctness and validity of the model. Then, we analyse the MIMO capacity in theory. Lastly, we simulate and analyse the effect of SNR and the number of antennas on the MIMO channel capacity.