Abstract: A one year field experiment was conducted once to access the effect of plastic film mulching on emerging time, changes of water content in soil surrounding root, biological yield,average yield and commodity rate of potato in dry land. The results showed： Comparing with open field cultivation,plastic film mulching cultivation reduced the growth period of potato by 15 days,increased the dry matter content of the plant significantly,improved both the average yield of tubers by 605.8kg/667m^2 and the commodity rate of tubers by 19.2%.Plastic film mulching cultivation increased not only the yield but also the economic benefit.