Protein disulfide isomerases (PDI) play in the protein folding, assembly, and posttranslational modification. In present study, a protein disulfide isomerase (PDI) cDNA sequence from Bactrocera dorsalis(BdorPDI) was cloned using the reverse transcription PCR (RT-PCR) compound with rapid amplification cDNA ends (RACE) method. The open reading frame (ORF) of BdorPDI is 1 497 bp in length and the deduced peptide contains 498 amino acids residues. Primary structure of the sequence reveals the typical characteristics of PDI family: signal peptide in the N-terminal, two CGHC active-site sequence motif in the N- and C- terminal, and retention signal KEDL at its C-end. Phylogenetic analysis show that Bactrocera dorsalis PDI shared the lowest sequence identity (49.3%) with PDI(XP_003217370) from Anolis carolinensis, and the highest sequence identity （76.3%） with PDI (ADD20271) from Glossina morsitans.Real-time PCR results indicated that BdorPDI expressed during whole developmental stages. The relative expression level in larvae was lower but gradually increased during the developing from 1-instar larva to 3-instar larva. The expression level in 1 d- old pupa reach a peak and the amount is about 536.50 folds of that in the baseline. The amount of the BdorPDI mRNA gradually decreases during the pupa development.The results implied that Bactrocera dorsalis PDI play an important physiological role in the pupation procession.