Abstract: Thymosin β4 has antibacterial properties and inflammation inhibition function which can promote wound healing. This study cloned the gene sequence of Pfthymosin β4 from Pinctada fucata. The total length of the gene was 261 bp, with 126 bp open reading frame encoding 42 amino acids. Bioinformatics analysis reveals that the theoretical molecular weight of Pfthymosin β4 was 4.78 ku, which had typical “THY” motif and thymosin beta family signature sequences. It was highly conserved and had more than 90% similarity to other species. The results of qPCR show that Pfthymosin β4 was expressed in all tissues with the highest expression in hemolymph, followed by foot and gills. Hemolymphs and wound tissues were collected after the mantle-transplantation. The expression of Pfthymosin β4 in hemolymphs and wound tissues increased significantly and reached the maximum at 6^th hour, which might be the reason that it promotes hemolymphs to move to the wound to participate in the wound pre-repair. The expression level of Pfthymosin β4, which elevated at metamorphosis stage, was detected at each developmental stage of P.fucata. Therefore, it is speculated that Pfthymosin β4 might be involved in metamorphosis of P.fucata.