Monochamus saltuarius is an important vector of pinewood nematode in Eurasia with a high reproductive capacity. Endocrine hormones play a key role in insect reproduction. Understanding the mechanism of internal regulation can provide targets for pest control. However, this type of research on M. saltuarius remain limited. Our study constructed transcriptome of the internal reproductive systems in male and female M. saltuarius across three development stages. Interference experiments targeting the MSALMet1 and exploring its critical role in reproduction. Transcriptome results revealed that 42 genes related to the juvenile hormone and ecdysteroid pathways were identified. Among them, 12 genes were significantly enriched in reproduction-related pathways, and the expression patterns of 14 genes aligned with the developmental trend of the internal reproductive system, suggesting that they may play a regulatory role in reproductive processes. Furthermore, protein-protein interaction networks elucidated the complex interactions among these genes, shedding light on their diverse functions. Notably, bioinformatics analysis and interference experiments revealed that MSALMet1 having the profound effect on reproductive system development in both sexes. These findings highlight the critical role of endocrine-related genes in regulating reproductive development and provide a theoretical foundation for regulating reproduction at molecular level, potentially contributing to M. saltuarius population control.