[Objectives]  To improve understanding of the characteristics and expression profile of the Cnaphalocrocis medinalis ABCG3 protein, one of the ATP-binding cassette transporter (ABC transporter) transmembrane proteins found in many organisms that is involved in the transport of nutrients and exogenous toxins. [Methods]  We used bioinformatics to investigate the molecular properties of the C. medinalis ABCG3 transporter protein, and RT-qPCR to determine its expression patterns in different larval instars and tissues. [Results]  C. medinalis ABCG3 is a half-transporter protein with 1 055 amino acids, a molecular weight of 118.95 ku and an isoelectric point of 8.78. It has a transmembrane domain (TMD) and a nucleic acid binding domain (NBD). The protein is predicted to be located in the endoplasmic reticulum, and has a 43.51% α-helix, a 7.01% β-angle, a 18.29% lamellae and a 31.18% irregular roll. A phylogenetic tree of C. medinalis ABCG3 and that of five other lepidopteran species suggests that C. medinalis ABCG3 is most closely related to that of the monarch butterfly (Danaus plexippus). The ABCG3 gene was found to be expressed in all larval instars and tissues that were investigated. Expression was higher in fifth instar larvae than in other instars, and higher in the hemolymph and fat body than in other tissues. [Conclusion]  These findings clarify the structural properties and expression patterns of the ABC transporter family in C. medinalis, and thereby provide a platform for further investigation of the function of ABC transporters in this species.