The corn borer is a world-wide agricultural pest. In this study, a full-length neuropeptide F (npf) gene in Ostrinia furnacalis was sequenced and cloned from a cDNA library, in which the npf gene produces two splicing mRNA variants - npf1 and npf2 (with a 120 bp segment inserted into the npf1 sequence to generate npf2). A spatio-temporal expression analysis showed that the highest expression level of npf was in the midgut of 5 instar larvae (the gluttony period), and their npf expression and food consumption were significantly promoted after food deprivation for 6 h. When npf was knocked down by double-stranded RNA for NPF, larval food intake, weight and body size were effectively inhibited through changes of a biosynthesis and metabolism pathway; i.e. gene silencing of NPF causes decreases of total lipid and glycogen and increases of trehalose production. Moreover, we produced transgenic corn plants with stably expressed dsNPF. Results showed that O. furnacalis larvae fed on these transgenic leaves had lower food consumption and smaller body size compared to controls. These results indicate that NPF is important in the feeding control of O. furnacalis and valuable for production of potential transgenic corn.