[Aim]  To investigate the impact of chitin synthase (CHS) on the growth and development of Frankliniella occidentalis, aiming to identify a potential target for controlling F. occidentalis. [Methods]  The CHS gene of F. occidentalis was cloned and named Fochs, and its function was investigated using RNA interference (RNAi) technology. [Results]  The full-length open reading frame of the Fochs gene was 4 656 bp, encoding 1 551 amino acids, and the predicted molecular weight was 176.02 kD. The conserved domain was Glyco-tranf-GTA-type superfamily. The phylogenetic tree indicated that the Fochs had the closest genetic relationship with the CHS of Thrips palmi. RT-qPCR results demonstrated that the Fochs gene was expressed at all stages of the growth and development of F. occidentalis, with the highest expression in the 2nd instar nymphs, followed by the pro-pupae. After silencing Fochs for 120 h, the mortality rates of the 2nd instar nymphs and pro-pupae was significantly increased (P < 0.01), while the pupation rate and eclosion rate was significantly decreased (P < 0.01). Both nymphs and pupae exhibited morphological changes such as wrinkled cuticle, reduced body size, and deformity, with almost no effect on newly eclosed adults. [Conclusion]  The chitin synthase gene plays a significant role in the growth and development of F. occidentalis, making it a potential target for precise and environmentally friendly control through RNAi-mediated approaches.