This paper explores the impact of property rights reform on the performance of Chinese State-owned enterprises (SOEs), by using the firm level data of the iron and steel industry collected by the third industrial census implemented in 1995 and materials of Ministry of Metallurgical Industry. Estimating Cobb-Douglas type production function with the fixed effect model, it is found that, 1) the property rights reform, represented by the ratio of non-state capital to total capital, significantly contributed to the productivity of firms transformed to stock company but not SOEs ; 2) compared to the ownership of capital by state, ownership by corporation has a positive effect on productivity of the stock company.