Objective To investigate the resistance of Culex pipiens quinquefasciatus to chemical insecticides commonly used in heavy disaster areas of the 5·12 Wenchuan Earthquake, Sichuan province, China, and to provide a reference for more scientific and rational selection and use of public health insecticides. Methods Mosquito larvae were collected from heavy disaster areas of the 5·12 Wenchuan Earthquake in Sichuan (experiment group) and non-heavy-disaster area in the urban district of Chengdu (control group). Additionally, standard susceptible strain was obtained from the insectaria of Sichuan Center for Disease Control and Prevention (control group). The dipping method was used to test the resistance of mosquito larvae to insecticides. Data were statistically analyzed using SPSS 17.0 to determine the median lethal concentration (LC₅₀) and resistance grades. Results Compared with the control larvae, the experimental larvae showed significantly high resistance to beta-cypermethrin, with resistance ratios (RRs) of 2925.00 in Beichuan county, 1250.00 in Dujiangyan city, 2375.00 in Qingchuan county, and 1075.00 in Wenchuan county. To deltamethrin, the larvae in Beichuan and Dujiangyan showed high resistance (RR 90.59 vs. 71.77), while those in Qingchuan and Wenchuan showed moderate resistance (RR 14.12 vs. 21.18). All of the experimental larvae showed low resistance to dichlorvos (RRs 9.85, 5.29, 5.90, and 7.05). To Bassa, the experimental larvae showed reduced susceptibility in Beichuan, Dujiangyan, Wenchuan, and Qingchuan (RRs 3.90, 3.12, 3.83 and 1.57). Conclusion Culex pipiens quinquefasciatus larvae developed significantly high resistance to beta-cypermethrin and deltamethrin in heavy disaster areas of the 5·12 Wenchuan Earthquake. According to the usage of insecticides after earthquake, the high insecticide resistance of Cx. pipiens quinquefasciatus was relevant to massive uses of pyrethroid and organophosphorus insecticides for control of harmful insects.