Abstract: From the viewpoint of system science, this paper makes a quantitative analysis of the problem about sustainability degree of agricultural sustainable development. First, by using efficacy function and stochastic simulation for time sequence, the theoretical computation models of sustainability degree for agricultural sustainable development system were set up. On the basis of this work, the practical analysis of problem on computation and simulation for agricultural system of Zhejiang Province was made. The research result shows that computation model can adapt to many basic characteristics such as stochastic indefiniteness of agricultural system. The conclusion may provide important references for decision-making for the strategy for agricultural sustainable development of Zhejiang Province.