Simple Summary: Sex pheromone plays an important role in mediating mate communication for the tea black tussock moth, Dasychira baibarana, which is a devastating pest in Chinese tea plantations. The sex pheromone of this pest is a ternary blend, including two typical Type-II epoxides and one unsaturated ketone. This study investigated P450 candidates that are associated with the biosynthesis of the sex pheromone components. With a combination of comparative RNAseq, phylogenetic, and tissue expression pattern analysis, one CYP4G with abdomen specifically predominant expression profile was likely to be the P450 decarbonylase, and the pheromone-gland specifically and most abundant CYP341B65 was the most promising epoxidase. This research laid a valuable foundation not only for further functional characterization of P450 decarbonylase and epoxidase in the sex pheromone biosynthetic pathway but also for understanding the physiological functions and functional diversity of the CYP gene superfamily in the D. baibarana. The tea black tussock moth (Dasychira baibarana), a devastating pest in Chinese tea plantations, uses a ternary Type-II pheromone blend containing (3Z,6Z)-cis-9,10-epoxyhenicosa-3,6-diene (Z3,Z6,epo9-21:H), (3Z,6Z,11E)-cis-9,10-epoxyhenicosa-3,6,11-triene (Z3,Z6,epo9,E11-21:H), and (3Z,6Z)-henicosa-3,6-dien-11-one (Z3,Z6-21:11-one) for mate communication. To elucidate the P450 candidates associated with the biosynthesis of these sex pheromone components, we sequenced the female D. baibarana pheromone gland and the abdomen excluding the pheromone gland. A total of 75 DbP450s were identified. Function annotation suggested six CYPs were orthologous genes that are linked to molting hormone metabolism, and eight antennae specifically and significantly up-regulated CYPs may play roles in odorant processing. Based on a combination of comparative RNAseq, phylogenetic, and tissue expression pattern analysis, one CYP4G with abdomen specifically predominant expression pattern was likely to be the P450 decarbonylase, while the pheromone-gland specifically and most abundant CYP341B65 was the most promising epoxidase candidate for the D. baibarana sex pheromone biosynthesis. Collectively, our research laid a valuable basis not only for further functional elucidation of the candidate P450 decarbonylase and epoxidase for the sex pheromone biosynthesis but also for understanding the physiological functions and functional diversity of the CYP gene superfamily in the D. baibarana. [ABSTRACT FROM AUTHOR]