Aim To observe the changes of serine/threonine kinase 2(Akt 2)protein expression in pulmonary arteriy smooth muscle cells(PASMC) induced by hypoxia in rats,and to investigate the value of Akt 2 signaling pathway in hypoxia pulmonary hypertension(HPH). Methods The pure PASMC was cultured by tissue-sticking methods.Akt 2 protein expressions were determined by Western blotting after PASMC were exposed to hypoxia for 2 h,8 h,12 h and 24 h respectively.The changes of PASMC proliferation were determined by MTT and 3 H-TdR incorporated way. Results The value of 3 H-TdR was 0.372±0.059 under normoxia.And accompanying the prolongation of hypoxia time,the value of 3 H-TdR kept heightening.It was 0.703±0.100 in 12 h and significantly different from normoxia group;The value of MTT was 8374.39±545.31 under normoxia.And accompanying the prolongation of hypoxia time,the value of MTT kept heightening.It was 11208.35±678.82 in 24 h group and significantly different from normoxia group.The protein of Akt 2 could be detected in all groups,and the expressive level of protein showed a possible relationship with PASMC prolferation. Conclusion The results suggest that Akt 2 signaling pathway may play an important role in the hypoxia pulmonary hypertension.