In recent years, the antennas of MIMO system tends to be miniaturized, and the coupling effect becomes the main factor that affects the channel capacity. In this paper, the method of modeling the indoor SVA fading channel model is introduced firstly. Secondly, the principle of the coupling effect is presented. Finally, the coupling effect is brought into the channel model, and the effect of different antenna spacing on the channel capacity is analyzed under the multipath condition. Simulation results show that the coupling effect leads to the decrease of the channel capacity, and the shorter the antenna spacing, the greater the effect of the coupling effect on the channel capacity.