Venom of sea anemone Anthopleura qingdaoensis contains at least two cardiotonic polypeptides capable of enhancing cardiac contraction(a positive inotropic effect). An artificial gene encoding anthopleurin-QD2 (Ap-QD2), which consists of 49 anino acid residues, was cloned and transferred into pPICZαA, a secretory expression vector for Pichia pastoris. The construct was linearized and was integrated into the yeast chromosome by electroporation under the selection of zeocin. Approximately 20 mg/L of biologically active Ap-QD2 was produced from one of the KM71(Mut^s) transformants, and about 7 mg of pure Ap-QD2 was obtained after chromatography purification.