Abstract: Ownership structure is the arrangement of corporate authority. It determines the efficiency of corporate governance, and further affects corporate performance. The ownership structure was changed after the split-share reform. This paper is a study on the relationship between the ownership and performance of 237 listed companies who finished reform first. It was found that firms' performance is negatively correlated with the proportion of state-owned shares, negatively correlated with the proportion of individual shareholders and positively correlated with the legal person shares but very insignificant. The evidence also shows that the correlation between ownership concentration and firms' performance is positive.