Abstract: The community component of soil animals and seasonal changes in four fragments of tropical rain forest in Xishuangbanna were investigated.Seven samplings (50 cm×50 cm) in soil litter were examined from each of the fragment of tropical rain forest in dry and rainy season.The soil animals were collected by Tullgren methods.The results showed that the soil animal community were composed of 4 phylum 9 class 24-27 groups.Acarina and Collembola were preponderant groups,Hymenoptera,Coleoptera and Diptera were common groups.The coefficient of community of community components of soil animals of the primary forest in Menglun Nature Reserve and the forests of the three Holy Hills of Dai nationality were changed with season:in dry season,respectively as 0.52,0.68,0.60;in rainy season,as 0.72,0.82,0.81.The coefficient of community of the community components of soil animals of the four tropical forests in different season were 0.73,0.72,0.82,0.52 respectively.Diversity indexes (H) of the soil insects in the four forests were 0.60,0.91,0.71,0.75 respectively.The specific value (A/C) of Acarina and Collembola in the four rain forests were respectively as 1.14,5.24,2.52,2.38.The fragmentary rain forests of Holy Hills were higher than the primary rain forest in Menglun Nature Reserve.