The structures of bacterial communities in the brown planthopper(BPH) Nilaparvata lugens(St?l) from different geographic and resistant virulent populations were analyzed by using denatured gradient gel electrophoresis(DGGE). Results showed that the bacterial communities in BPH nymph from the first to the fifth instars varied with nymphal growth and development. The bacterial communities in the first-instar BPH nymph were similar to those in adults. Nine geographic BPH populations were divided into three groups based on the cluster analysis of DGGE fingerprint. The first group was from the Philippines; the second group was from Thailand and Hainan, Yunnan and Zhejiang provinces of China; and the third group was from Vietnam and Guangxi, Hunan and Jiangxi provinces of China. BPH populations adapted to different resistant rice varieties. The BPH populations from Mudgo(with resistant gene Bph1) and ASD7(with resistant gene bph2) differed with those of the susceptible rice variety TN1. The structures of bacterial communities in the brown planthopper (BPH) Nilaparvata lugens (St? L) from different geographic and resistant virulent populations were analyzed by using denatured gradient gel electrophoresis (DGGE). Results showed that the bacterial communities in BPH nymph from the first to the fifth instars varied with nymphal growth and development. The bacterial population in the first-instar BPH nymph were similar to those in adults. Nine geographic BPH populations were divided into three groups based on the cluster analysis of DGGE fingerprint. The first group was the second group was from Thailand and Hainan, Yunnan and Zhejiang provinces of China; and the third group from from Vietnam and Guangxi, Hunan and Jiangxi provinces of China. BPH populations adapted to different resistant rice varieties. The BPH populations from Mudgo (with resistant gene Bph1) and ASD7 (with resistant gene bph2) differed with those of the susceptible rice variety TN1.