Plastic film mulching is widely used in tropical Hainan island. The objective of this study was to explore the effects of different colors of plastic film mulching on pumpkin yield，quality and soil carbon and nitrogen activity status in winter and to provide scientific basis for improving soil fertility under plastic film mulching. In 2020，a field experiment of plastic film mulching was conducted in Haikou，Hainan province. Five treatments with three repetitions were set up，including no plastic film mulching control treatment，white，black-white，black and silver-black plastic film mulching treatments，to study the effects of different colors plastic film mulching. The results showed that black and silver-black mulching significantly improved the yield and quality of pumpkin. The average weight of each fruit in black and silver-black mulching treatments exceeded 4 kg，and the yields were 112.20 t/hm² and 102.45 t/hm²，respectively. The single fruit weight，yield per unit，fresh fruit weight and dry fruit weight of the two groups of treatments were 4 times greater than those of the control treatment. The soluble sugar was about 3 times that of other treatments. Black film and silver-black film mulching reduced soil organic matter and total nitrogen content，increased soil active nutrient content，and improved the ratio of soil active carbon to nitrogen. After a pumpkin growth period，the highly active organic matter of the soil treated with black and silver-black plastic film was 4.67 and 5.20 g/kg，which was about 4 times that of other treatments，and the alkali-hydrolyzed nitrogen was 61.37 and 77.12 mg/kg，respectively，extremely significantly higher than other treatments. Black and silver-black plastic film mulching can reduce the total soil nutrient organic matter and total nitrogen content，and rapidly accumulate active organic matter and alkali-hydrolyzed nitrogen content，thereby significantly improving the yield of pumpkin in tropical Hainan island in winter.