[Aim]  To clarify the susceptibility of Spodoptera exigua in Shanghai to commonly used insecticides and provide a scientific basis for its control. [Methods]  The diet-overlay method was used to determine the susceptibility of wild populations of S. exigua in suburban Shanghai (Fengxian, Jinshan, and Jiading districts) to three insecticides (cyantraniliprole, emamectin benzoate, and spinetoram). PCR technology was used to detect the mutation frequencies of resistance-related gene loci in these populations, including the ryanodine receptor (RyR), the nicotinic acetylcholine receptor (nAChRα6), and the cytochrome P450 enzyme (CYP9A186). [Results]  The Jinshan population had a high-level of resistance to both cyantraniliprole and emamectin benzoate, whereas the Fengxian and Jiading populations had moderate resistance to these two insecticides. All three populations remained highly susceptible to spinetoram. The frequency of resistant alleles at the I4743M site of the SeRyR gene ranged from 92.0% to 100.0%. The G4900E mutation was not detected. The frequency of resistant alleles at the F116V site of the CYP9A186 gene ranged from 75.0% to 96.0%, whereas that at the G275E site of the nAChR α6 gene ranged from 14.0% to 26.0%. [Conclusion]  Spodoptera exigua populations in Shanghai have moderate to high resistance to cyantraniliprole and emamectin benzoate but remain susceptible to spinetoram. Rotating the use of insecticides, or using non-cross-resistant insecticides, could be crucial for the effective management of S. exigua in this region.