Abstract: To achieve a reasonable development of agriculture in Heilongjiang Province, agricultural system of Heilongjiang was analyzed from the perspective of complex system and divided into four parts, including agricultural-economic subsystem, agricultural-technical subsystem, rural social subsystem and agricultural-environmental subsystem. System dynamics model for sustainable development of agriculture in Heilongjiang Province was established and optimized by the parameter estimation and validity check based on Vensim DSS software and “Heilongjiang Province Statistical Yearbook” and other historical data through analyzing the influencing mechanism and correlation among these subsystems. Then, the sustainability of each subsystem in Heilongjiang Province from 2005 to 2020 was simulated and forecasted. The results showed that sustainability of agricultural economy was the best, followed by that of agricultural technology, social and ecological sustainability of agriculture were the worst.