[Aim] The important premise of insecticidal activity of Bt toxins is that they can bind to specific receptors on the brush marginal capsule (BBMVs) of the epithelial cells in the insect midgut. Based on the full length sequence of the aminopeptidase N(APN) gene of Chilo suppressalis, the binding ability of APN1 to Cry2Aa toxin was determined.[Method] APN1 of C. suppressalis was expressed in Escherichia coli BL21 (DE3). The binding ability of APN1 of C. suppressalis to Cry2Aa was analyzed by one dimensional electrophoresis and a ligand blotting assay.[Result] The recombinant vector expressed a 70 ku protein in the BL21(DE3) strain, which indicated that the prokaryotic expression vector was successfully constructed. SDS-PAGE showed a single protein band, indicating purity. Ligand blot results showed that APN1 recombinant protein could bind to Cry2Aa. The width of the binding band decreased with decreasing recombinant protein sample volume.[Conclusion] APN1 could bind to the Cry2Aa toxin, which lays a foundation for elucidating the function of APN1 gene and provides a new reference for the study of other Bt receptors.