Abstract: In July 2020, shoots (40 cm) of Cinnamomum cassia with worm-eaten character were collected from Qinzhou, Guangxi and were feed inlab. Observations were made on morphological properties of pupa and adult of P. cassiicola. The result showed that terminal abdomen of female pupahad no obvious segmentation, no strumae, and had distance between gonopore and excretory pore. Male pupa had a longitudinal fissure on the 9thabdominal segment, which was longer than that of the female one, with hemispherical strumae on both sides, and the distance between gonopore andexcretory pores was close. The terminal abdomen of female moth was plump and round, with long and yellow tail hair. The male moth had a long andslender abdomen, with neat brown short hair cluster on the tail. Identification of sex of P. cassiicola was based on morphological properties of pupaand adult.