With reference to several possible solutions to the issue of two subject allocation, using the Accumulation Point analysis method in Game Theory, this paper analyzed the income distribution mechanism between large farmers and small farmers in farmer cooperatives in the context of membership heterogeneity. It found that, in the practice of the income distribution in farmer cooperatives, there possibly exists equalization solution, pure utility solution, Nash solution and Kalai-Smorodinsky solution and it will be affected by social conventions. Finally, it made an empirical analysis using five cases of farmer cooperatives.