Phospholipase A2 (PLA2) is one of the components of bee venom with a wide range of pharmacological functions. It operates as a major allergen working with other venom components to defend the colony from intruder. In the present study, the cDNA sequence of the Ac-pla2 gene from cDNA library of the venom gland of Apis cerana was compared with the amplified corresponding region of genomic DNA. The result showed that the Ac-pla2 gene consisted of four exons and three introns. Southern blot showed that the Ac-pla2 gene was a single copy per haploid genome. The most active transcription period was during the first 8 days of adults, which correspondingly was the period of sharp increase of PLA2 protein. ELISA analysis revealed that the PLA2 was undetectable in pupal stage and the newly eclosed adult, but increased sharply to a maximum of 10-12μg per honeybee by 8-10days of adult life, followed by a gradual decrease to 8μg for the rest of adult life. Transcriptional or post transcriptional regulation is the key step for Ac-pla2 expression. The early secreted Ac-PLA2 showed a low degree of posttranslational modification; with increasing age, glycosylation was detected by Western blot and glycoprotein staining analysis. Different post-translational modifications were found among different individuals in A. cerana when compared to A. mellifera. Arch. Insect Biochem. Physiol. 60: 1-12, 2005.