Abstract: 【Objective】The study was to explore the feasibility of feeding target gene dsRNA expressed by HT115- mediated RNAi in Bactrocera dorsalis(Hendel) fl ightin gene.【Method】The RNAi fragment of fl ightin from B.dorsalis was inserted into L4440 dsRNA interference vector, and transformed into E.coli HT115 (DE3). The dsRNA corresponding to fl ightin, designated as fl ightin-dsRNA, was expressed by IPTG induction.【Result】Real-time quantitative PCR analysis revealed that the expression of fl ightin in B.dorsalis was generally up-regulated in different degrees by feeding 10-fold concentrated bacterial solution expressing fl ightin-dsRNA to B.dorsalis. Among which, there were significant differences between females after feeding for 5, 10 and 20 days, males after feeding for 5 days and the control, and about 43% downregulation was induced in males after feeding for 15 days. The flight ability and chest muscle development of B.dorsalis were not affected significantly. 【Conclusion】The feasibility by feeding E.coli HT115(DE3) expressing fl ightin-dsRNA to interfere with the fl ightin gene of B.dorsalis needs to be further confirmed.