Species richness of phytophagous insects in plantation of transgenic insect-resistance hybrid poplar 741 was obviously lower than that of neutral arthropod. The individuals of intermediate and top species apparently increased. In arthropod community, the superiority of phytophagous dominant functional groups was higher than that of CK, and the superiority of predator and parasitoids ascended. In arthropod community of the transgenic insect-resistance hybrid poplar 741, the superiority of neutral arthropod increased, and it played an important regulating role in the natural enemy-pest trophic chain. The spatial niche breadth of target pests was least, and the niche breadths of other functional groups were relatively wide. Predators and parasitoids had a narrower niche overlap with the target pest, but had a wider niche overlap with the neutral species. There are severe competition among pests and between predators and parasitoids. The transgenic insect-resistance hybrid poplar 741 had a positive effect on the natural enemies in utilization of time resources. The values of ecological niche breadths of double dimension and niche overlaps in all kinds of functional groups were not as much as those of single dimension niche, yet natural enemies in transgenic insect-resistance hybrid poplar 741 could be better adapted to environment than those in control.