In order to study the impact of institutional change on agricultural economy,this paper establishes an evaluation system on institutional change,including marketization degree,non-stateowned rate,industrial rationalization degree,opening degree and urbanization rate.An empirical study is conducted by using the entropy evaluation method to calculate the degree of institutional change and a Markov Switching Vector Autoregressive model to analyze the nonlinear characteristics of the impact.The results show that the agricultural economy,obviously featured by state transition and stage characteristics,changes frequently between moderate regime and heavy regime which can be divided into five stages,namely 1979-1981,1982-1986,1987-1991,1992-1996 and 1997-2015.Besides,the impact of institutional change on agricultural economy is long-termed and differentiated,and the impact in the heavy regime is more obvious than that in the moderate regime.Furthermore,the impact of institutional change on farming economy is negative,yet positive on forestry,stock farming and fishery,among which fishery is most-seriously influenced,closely followed by forestry,stock farming and farming.