Chemosensory systems play key roles in the survival and reproductive success of insects. Two large and diverse chemosensory gene families, odorant receptors (ORs) and odorant binding proteins (OBPs) play critical roles in insect chemosensation and mediate odor-guided behaviors. In the process of insect chemosensation, odorants from the environment pass through pores in the antennal sensilla and become soluble in the sensillar lymph, either directly on contact or by binding to an OBP. Solubilized odor molecules diffuse through the lymph until they reach and activate their cognate ORs, sending electrophysiological signals to the insect brain. To better understand the evolutionary roles of OR and OBP gene families among members of the Heliothinae, we systematically characterized these two gene families in Chloridea virescens. A total of 81 ORs and 49 OBPs were identified genome-wide. Based on the number and positions of conserved cysteine residues, the OBPs were classified into three types: 34 Classic OBPs, 8 Minus-C OBPs, and 7 Plus-C OBPs. Phylogenetic analyses identified potential gene duplications and losses within OR and OBP gene families among members of the Heliothinae, which may be associated with the differences in their volatile sensation and olfactory behaviors. Further motif and structural analysis identified a conserved region that was unique among pheromone receptors and predicted as key residues of the binding pocket, implying its critical role in pheromone detection. Future directions would focus on experimentally validating its function.