The study investigated effects of mulching plastic film residue in mono-cotton planting system with mulched plastic film lasting for 20 years，and cotton-tomato，and mono cotton planting system mulched plastic film lasting for 10 years in Shihezi district. The result shows that there has been a very serious pollution. The average amount of residue of mulching plastic film remained in the cotton field soils is (300.65±49.32) kg·hm-2, and the distribution of residue is relatively uniformity in 0-30 cm layer. The amount of plastic film residue depends on duration of utilization of mulching plastic film，and the longer the duration of utilization，the more plastic film residue is left in the field. For the mono cotton planting system mulched plastic film for 10 years and 20 years，the amount of plastic film residues are (307.9±35.84)kg·hm-2 and (259.7±36.78)kg·hm-2，respectively. At the same time，it is found that the amount of plastic film residue is also affected by the planting method. For the cotton-tomato rotation system mulched plastic film lasting 20 years，the plastic film residue gave a maximum value of about (334.4±47.88)kg·hm-2. The results also indicate the number of plastic film residue pieces are from 10 to 20 million per hectare, most of them are distributed in 0-10cm soil layer and most of the residue pieces are of small size area of about 1-25 cm2 and over 80% of the residue piece are less than 25cm2.