The soluble carrier proteins, OBPs carry odor components through sensilium lymph tospecific receptors within the antennal sensilla to trigger behavioral responses. Herein,McinOBP4 was characterized from the Macrocentruscingulum, which is the specialistparasitic insect of Ostriniafurnacalis for better understanding of olfactory recognitionmechanism of this wasp. The classical odorant binding protein McinOBP4 showedgood binding affinity to corn green leaf volatiles. RT-qPCR results showed that theMcinOBP4 was primarily expressed in male and female wasp antennae, with transcriptslevels differing by sex. Fluorescence assays indicate that, McinOBP4 binds corn greenleaf volatiles including terpenoides and aliphatic alcohols as well as aldehydes withgood affinity. We have also conducted series of binding assay with first mutant (M1),which lacked the last 8 residues and a second mutant (M2), with Met119 replaced byLeucine (Leu119). In the acidic conditions, affinity N-phenylnaphthylamine (1-NPN) toMcinOBP4 and M1 were substantially decreased, but increase in basic condition withno significant differences. The lack of C-terminus showed reduced affinity to terpenoidesand aliphatic alcohols as well as aldehydes compounds of corn odorants. The mutantM2 with Met119 showed significant reduction in binding affinity to tested odorants, itindicating that Met119 forming hydrophobic chain with the odorants functional group tobinding. This finding provides detailed insight of chemosensory function of McinOBP4 inM. cingulum and help to develop low release agents that attract of this wasp to improveecologically-friendly pest management strategy.