Abstract: An investigation was conducted in 6 different types of Finns massoniana stands (different age and canopy density of stands) in Jing County, Hunan Province to study the insect communities (including spiders) and its structure of time and space. None of the 688 species collected showed that it had the community. The distribution of each species of insect or spider was comparatively even. The results of the investigation indicated that stabilities of insect communities were different in the stands which had different ages and canopy densities. Stand age has more influence on the stability of insect community than canopy density does. In this paper we tried to use the natural enemy/ pest (NE/P) and the year extreme difference of diversity indices of insect community to discuss the stability of a community, and tried to explain the main causes which affected the stability. The more the number of natural enemies, the bigger the value of NE/P. Stands with bigger values of NE/P have more self-control abilities and make the insect community more stable.