Trehalose is the major blood sugar in insects, which plays a crucial role as an instant source of energy and the starting substrate for chitin biosynthesis. In insects, trehalose is synthesized by catalysis of an important enzyme, trehalose-6-phosphate synthase (TPS). In the present study, a trehalose-6-phosphate synthase gene from Bactrocera minax ( BmTPS ) was cloned and characterized. BmTPS contained an open reading frame of 2445 nucleotides encoding a protein of 814 amino acids with a predicted molecular weight of 92.05 kDa. BmTPS was detectable in all developmental stages of Bactrocera minax and expressed higher in the final- (third-) instar larvae. Tissue-specific expression patterns of BmTPS showed that it was mainly expressed in the fat body. The 20-hydroxyecdysone (20E) induced the expression of BmTPS and three genes in the chitin biosynthesis pathway. Moreover, injection of double-stranded RNA into third-instar larvae successfully silenced the transcription of BmTPS in B. minax , and thereby decreased the activity of TPS and trehalose content. Additionally, silencing of BmTPS inhibited the expression of three key genes in the chitin biosynthesis pathway and exhibited 52% death and abnormal phenotypes. The findings demonstrate that BmTPS is indispensable for larval-pupal metamorphosis. Besides, the establishment of RNAi experimental system in B. minax would lay a solid foundation for further investigation of molecular biology and physiology of this pest. [ABSTRACT FROM AUTHOR]