The corn borer is a world-wide agricultural pest.  In this study, a high-efficiency RNAi method was explored to knock down the neuropeptide F (NPF) to determine if NPF regulates larval feeding in the Asian corn borer, Ostrinia furnacalis.  Results showed that the expression peaks of npf mRNA in both midgut and fat body are at 28 h of early 5th instar larvae.  When NPF was knocked down either by feeding dsNPF-containing artificial diet or direct dsNPF injection into the 5th instar larvae, npf expression was effectively inhibited in the midgut.  Larval feeding, body weight and development time were significantly impacted.  In contrast, the expression of the npf receptors npfr1 and npfr2 in fat body of 5th instar larvae was significantly increased by dsNPF injection.  These results indicate that NPF can be effectively knocked down in O. furnacalis, and dsNPF by injection is an effective and fast way to silence npf expression.  This study provides a critical basis for further exploration in mechanism of feeding regulation in O. furnacalis.