Abstract: To understand the composition and diversity of insect communities in flax fields in Guyuan, consider pest control in community level, and provide a reference for pest integrated management, insect species and numbers in Touying Town and Zhanngyi Town in Guyuan flax fields were investigated by sweeping method. The results showed that there were 59 species of insects which were belonged to 35 families, 9 orders, including 43 species of pests (27 families , 7 orders) and 16 species of pests (9 families, 5 orders). The dominant pests were Yamaphis yamana Chang, Adelphocoris lineolatus, Phytomyza atricornis and Odontothrips loti. The natural enemy insects were mainly Adonia variegata, Harmonia axyridis and Chrysoperla sinica Tjeder. The number of insect species in Touying was more than that in Zhangyi, and reached the maximum at full bloom stage. Community characteristic index of flax field in high altitude was more than that in low altitude in Touying, indicating that community characteristic index in Touying might be related to altitude. Community characteristic index of Zhangyi was relative stable, and might be related to flax growth condition and environment. The similarity coefficients of insect communities of the villages in Touying showed differences. Similarity coefficients of Zhangyi was greater than that of Touying, meaning that the relationship of insect community in Zhangyi was more closer. This study obtained some basic data of the composition of insect communities in flax fields in Guyuan, analyzed the differences in different areas, and provided basis for pest control and scientific management.