Abstract: In order to further understand the effects of plastic film mulching on soil ecosystem, this paper studied the structure of soil nematode trophic groups and life history groups. The results showed that the relative density of Basiria, Aphelenchus, Filenchus, Tylencholaimus, Acrobeloides, Acrobeles was more than 10%, and the order of individual soil nematode in every 100g dry soil in different treatments was Covering 1 year>Not covered>Covering 4 years. Plastic film mulching affected the number and relative density of soil nematode trophic groups and life history groups. The number of fungi-feeding nematodes, bacterial-feeding nematodes and plant parasitic nematodes decreased significantly in Covering 4 years, and the number of omnivore-predator nematodes was stable, while the relative abundance was significantly increased. On the other hand, the number and relative abundance of c-p2 were significantly decreased, while c-p4 increased. No significant differences were found in the F/B and NCR among different treatments. The soil decomposition was mainly depended on the bacterial decomposition pathway in all the surveyed maize fields. The MI、MI2-5、MMI、MMI2-5 and PPI were significantly increased in the 4-year treatment, which showed that the stability of soil ecosystem was increased by 4-year continuous mulching in maize fields. Therefore, the change of the composition and structure of nematode community has effective bio-indication on the soil ecosystem of maize fields.