Abstract: High- ridge and soil cover on the plastic films for potato planting is a new potato cultivation technique popularized in these years, it has the advantages of high mergence rate, high yield and less weeds. The thickness of soil over the films is one of the key factors for natural emergence of potato. Five thicknesses (0, 1, 3, 5 and 7 cm) were set up to study the optimum thickness of covering soil. The results showed that the optimum treatments were 3 cm and 5 cm, which had the emergence uniformity of 91.7% and 91.4%, the yield increase of 28.83% and 27.72% over that of CK, the commodity rate improvement of 47.77% and 49.64%, and a decrease of weeds under the films of 44.74% and 84.21% respectively. Meanwhile, the recovery of plastic films was more completely.