A cDNA encoding a basic phospholipase A₂ (A.aBPLA₂) from Agkistrodon acutus was inserted into a bacterial expression vector pBLMVL2 and effectively expressed in E.coli RR1. The protein was produced as insoluble inclusion bodies. After partial purification by washing the inclusion bodies with Triton X-100, denaturing and refolding, the renatured recombinant protein was purified by FPLC column superose^TM12. The enzymatic activity of the expressed A.aBPLA₂ is close to those of denatured-refolded native acidic phospholipase A₂ from Agkistrodon halys Pallas, A.aBPLA₂ has the same hemolytic activity as denatured-refolded basic phospholipase A₂ from Agkistrodon halys Pallas, but its inhibiting effect on platelet aggregation is negligible. The roles of various amino acid residues in the enzymatic activity and pharmacological activities of phospholipase A₂ are discussed.