China passed its plant variety protection act(PVPA) in 1997 and it has effects on Chinese breeds market and new technologies adoption of farmers,which causes extensive concern of the academic circles.We use a system model to study the impact of PVPA on seed prices and planted area for plant variety.We find out that protected varieties have higher prices than unprotected varieties.In the applying stage,PVP doesn't show much impact on seed price,but lead to the 33% decrease of planted area at the same time.After the new species acquires the protection authorization,the seed price will increase to 1.63 yuan/kg,but it doesn't show much impact on planted area.