In order to solve the premature rupture of degradable mulch film due to degradation, the stability and degradation of PPC plastic film were studied under different mulching methods. The six mulching methods in the field were as follow: single-layer black PPC plastic film (SB), single-layer white PPC plastic film (SW), double black PPC plastic film (DB), double-white PPC plastic film (DW), double-layer mulch which upper layer was black and the lower layer was white (DBW), the double layer mulch which upper layer was white and the lower layer was a black (DWB). The infrared spectrum characteristics, mechanical properties and molecular weight of film periods were determined at a different time to judge the degradation of the plastic film under different treatments. The results showed that plastic film was exposed to conditions for a long time, and the toughness of plastic film has become worse. The main chain in the molecular structure was broken, furthermore, the relative intensity of the absorption peak of the C-H bond and C-O bond decreases with the increase of time. Due to the degradation of mulch film under the action of water molecules and microorganisms, the relative intensity of theCO stretching vibration peak and C-O-C antisymmetric absorption peak increased in different degrees. Due to the adhesion of molecular chain activity under sunlight, the stability of double-layer plastic film was higher than that of single-layer plastic film. Therefore, the decreasing trend of peak intensity for black and white double-layer plastic film DWB and DBW was more stable than that for single mulching film. The degradation degree was more slowly. The molecular weight and mechanical properties of each treatment showed a downward trend. The molecular weight. Tensile strength and elongation at the break of the double-layer plastic film were significantly higher than that of single-layer plastic film treatment. The stability of DWB and DBW treatments was stronger than that for the single mulching film within 30~150 days. The elongation at break and tensile strength of DWB and DBW treatments were 117.66%～120.39%, 151.69%～175.20% and 18.28～13.95, 15.35～9. 81 MPa at 150 days. The average molecular weights and number average molecular weights of DWB and DBW treatments were 72 663, 66 555 and 62 416, 66 555 g·mol-1. Comprehensive analysis showed that black and white double-layer plastic film could slowly cause the rupture of the plastic film caused by the degradation of PPC plastic film, Which could improve the time for the performance of water conservation and soil moisture conservation and better take advantage of the double-layer mulch film. After the optimization of the coverage methods of PPC plastic film, PPC plastic film could maintain its stability during the crop growth period, and it also could be degraded like a single layer mulch film after the crop growth period, which provided a theoretical basis for the further use of PPC film in agricultural production.