The community of arthropods in rice paddies was sampled at three locations over two years. The arthropods captured were divided into five feeding guilds: phytophages, parasitoids, predators, detritivores and others. The effects of two transgenic Bacillus thuringiensis cry1Ab japonica lines (KMD1 and KMD2) were evaluated in terms of guild dominance, family composition and dominance, as well as several indicdes of diversity. The control community was the one present on the untransformed parental rice line Xiushui 11. Compared with the control paddies, the guild dominance, species richness (S), Shannon-Wiener′s diversity index (H′) , evenness index （J） and Simpson′s dominance index （C）, and the temporal dynamics of Bt rice paddies showed no significant difference at the most situation. The dissimilarities between phytophagous sub-communities, parasitoid sub-communities, predator sub-communities and arthropod communities as a whole in Bt rice plots and the control were apparently low. It was apparent that the transgenic cry1Ab japonica rice has no negative effect on the rice paddy arthropod community.