Abstract: By the field experiment, the ecological effects of plastic film mulching cultiva tion of potato were studied. The results indicate that compared with the traditional cultivation, the available nitrogen and phosphorus in plough soil layer of plastic film mulching cultivation can be increased by 32.6%～64.0% and 4.2%～ 59.4%, respectively, the amounts of absorbing nitrogen and phosphorus can be in creased by 13.2%～48.3% and 14.6%～38.2%, respectively. The content of avail able nitrogen in plough layer at the vegetative stage is higher than that at the reproductive stage, but opposite for available phosphorus. Water content in plough layer of plastic film cultivation is 5.3%～31.6% more than that of traditional cultivation on vegetative stage, and absorbing water is increased by 26.3% ～31.0%. At the reproduction stage, water content is 1.9%～16 .9% more than that of traditional cultivation, absorbing water is increased by 4.4%～18.8%. At the vegetative and reproduction stages of plastic film mulching cultivation, bacteria in plough layer soil is increased by 30.0% and 130.8%, actinomyces is incre ased by 19.7% and 474.1%, mould is increased by 12.5% and 22.7%, respectively. Temperature of plastic film mulching cultivation in plough layer is higher than that of traditional cultivation; soil temperature is higher as the soil layer becomes deeper at the vegetative stage, but lower at the reproduction stage in the morning. Soil temperature is decreased as soil layer deeper at both stages at noon and in the afternoon. The yield of tuber, dry mass of shoot and root on plastic film mulching cultivation are higher than those of traditional cultivation. Appling more fertilizer increases the yield, nutrients and water content within the scope of experiment.