[Objectives]  To investigate the spatio-temporal expression and biological function of the Cut and Spalt genes in Spodoptera frugiperda during the development of the auditory organ. [Methods]  Full-length sequences of the Cut and Spalt genes were downloaded from the NCBI website and bioinformatics analysis performed. Quantitative Real-time PCR was used to detect the relative expression level of Cut and Spalt in different developmental stages and adult tissues. Interference fragments of Cut and Spalt were cloned with RT-PCR after which RNAi and qPCR were used to verify their effectiveness and observe the developmental phenotype of the resultant genetically modified insects. [Results]  The amino acid sequence of the S. frugiperda Cut gene is most similar to that of Spodoptera litura (99.19%), whereas the amino acid sequence of the S. frugiperda Spalt gene is most similar to that of Helicoverpa zea (97.15%). Cut and Spalt were expressed in all developmental stages and adult tissues; expression was highest on the 7th day of the pupal stage and in the heads of adults. Interference fragments for S. frugiperda Cut and Spalt, with lengths of 486 bp and 317 bp, respectively, were successfully designed and amplified. RNAi significantly reduced the relative expression of Cut and Spalt in 5th instar larvae, resulting in abnormal development of the auditory organ and wing in adults. [Conclusion]  Silencing Cut and Spalt down-regulated gene expression in larvae, thereby impairing normal development of the auditory organ and wing in adult S. frugiperda.