Bombyx mori is considered an alternative source of protein food due to its rich nutritional value. There has been a new upsurge of interest in the utilisation of insects as food during the last few years. Vacuolar protein sorting 4 (vps4) is known for its multifaceted role in biological processes such as lysosomal degradation, intracellular protein transport, and vesicle formation. It is known that H₂S can promote the growth and development of silkworms. Here, we used body cavity injection of siRNA to interfere with vps4 genes in H₂S-treated silkworms. The interference via injection of vps4 siRNA significantly decreased the body weight, cocoon weight, cocoon shell weight, egg laying and production in silkworms, without much effect on the cocoon shell ratio. H₂S treatment could significantly improve the inhibition of body weight, cocoon weight, cocoon shell weight and cocoon shell ratio by knocking down the vps4 gene in silkworms, without significant effects on egg laying and production. The interference of siRNA significantly decreased the expression of targeted vps4 gene and was concentrated in 24 h followed by gradual recovery. Three interference fragments also showed different interference effects, and siRNA of vps4-2 exerted the highest interference effect to the target gene expression. Fat body had the highest mRNA expression of vps4 gene, and the best interference effect was observed after siRNA injection. Our results suggest that there are significant phenotypic and genotypic effects of vps4 gene knockdown in silkworms, which is of great significance for future research on silkworms.