The mortgage loan of agricultural water right is beneficial to improving the value of water right, encouraging water saving, and also has a positive effect on increasing farmers’income, it is a new measure to practice green development. When the society has developed the mortgage model of agricultural water right, the stakeholders of this model are local government, commercial banks and farmers. In order to explore the mutual influence among three game subjects in the early development of mortgage mode of agricultural water right, this paper set up the trilateral evolutionary game, solved the evolutionary stable equilibrium point, and analyzed through evolutionary simulation. The conclusion shows that: the policy choices of different subject are easily affected by the changes of other subjects’policy choices, and the changes of key variables will affect the policy choices of each subject. Suggestions have been put forward to speed up water right confirmation, perfect the water right trading market, establish and improve relevant laws and regulations, strengthen incentives on local government, increase policy support for commercial banks, rebuild rural credit and improve the rewards and punishments, which can promote the effective development of the agricultural water right mortgage loan.