Abstract: 【Objective】 To study the variation characteristics of residual film amount in soil layer of 5, 10, 15, 20, 25, 30 a 0-40 cm. 【Methods】 (1) Each sampling point had 5 quadrats, each quadrat size was 100 cm×100 cm, and the residual film amount of 0-40 cm soil layer was measured layer by layer.(2) Investigation of the basic situation of plastic film recycling. 【Results】 (1) The order of soil residual film in 0-40 cm soil layer was 20 > 15 > 5 > 10 > 25 > 30 a, ranging from 92.83-195.13 kg/hm², with an average of 128.88 kg/hm².(2) With the increase of years, the order of residual film amount in 0-10 cm soil layer was 5 > 10 > 30 > 15 > 25 > 20 a, and the difference of residual film amount was not significant.The order of residual film amount in 10-20 cm layer was 15 > 20 > 30 > 10 > 5 > 25 a, and the residual film amount in 15 and 20 a was higher than that in 5, 10, 25 and 30 a, and the difference was significant.The order of residual film amount in 20-30 cm soil layer was 15 > 20 > 10 > 25 > 5 > 30 a, and the residual film amount in 15 and 20 a was high, which was significantly different from that in 5 and 30 a.The order of residual film amount in 30-40 cm soil layer is 20 > 25 > 5 > 15 > 30 > 10 a, and the residual film amount in 20 and 25 a is higher, which is significantly different from that in 5, 10, 15 and 30 a.(3) With the increase of soil depth: there is no significant difference in residual film amount between soil layers in 5 a; The residual film amount of 10 a 0-30 cm soil layer was not significantly different, and the residual film amount of 30-40 cm soil layer was significantly different from that of other soil layers.There were significant differences in the residual film amount between 10-20 cm and 0-10 cm and 30-40 cm soil layers at 15 a, and significant differences between 30-40 cm and 10-20 cm and 20-30 cm soil layers.There was no significant difference in the amount of residual film between the soil layers from 20 to 30 a. 【Conclusion】 (1) With the increase of mulching years, the amount of residual film in the 5-30 a 0-40 cm soil layer first increased and then decreased, reaching the peak at 20 a mulching, and showing a slight downward trend overall.(2) With the increase of mulching years, the residual film amount of 5-30 a 0-10 cm soil layer decreased first and then increased, and the overall trend was downward.The residual film amount of 10-20 cm soil layer increased first and then decreased, and the overall change trend was not obvious.The residual film amount of 20-30 cm soil layer first increased and then decreased, and the overall trend was slightly decreasing.The residual film amount in the 30-40 cm soil layer first increased and then decreased, and the overall trend was increasing.(3) With the increase of soil depth, the amount of residual film in each year of 5-30 a shows a downward trend, mainly accumulating in 0-30 cm, and a small amount of residual film in 30-40 cm.The 0-10 cm soil layer of 5 and 10 a is the main accumulation area.The main accumulation zone was the 10-20 cm soil layer at 15, 25, 30 a.The residual film amount of the 0-10 and 10-20 cm soil layers coated with film was basically the same.