After entering the soil, the degradation products of polyethylene film have a series of influences on ecological environment of the soil. The influences of the molecular weight and the cumulative amount of degraded polyethylene, soil type and soil depth burying polyethylene on the concentration of CO2 in the soil were investigated through the orthogonal test L9(34) . Collection and testing of CO2 were conducted by gas collector underground and the infrared detector of the Automatic Monitoring System of Soil. The change of CO2 in the soil at a growth cycle of maize was detected continuously by online monitor. The experimental data was analyzed using DPS data processing system. The results show that the impact of soil depth burying polyethylene on CO2 concentration increase with the increase of burying time, and the molecular weight of polyethylene has a decreasing impact on CO2 concentration with the increase of burying time. In the former period of the maize growth, the CO2 concentration is higher in the clay than in the sand and loam. But in the later growth stage the CO2 concentration in the loam are more abundant than other two soils.