After reform and opening up, the mixed ownership reform has been deliberated and developed for the last 20 years in the official documents of the Party. After the third plenary session of the 18th CPC Central Committee, this reform was positively promoted by the local governments. But on the level of firm, transaction attributes and transaction costs block the rapid advance of mixed ownership reform. On the level of nation, the mixed ownership reform is not privatization but is to perfect socialist basic economic system in the process of “joint advance” of multi-ownership economy to intensify public ownership economy. The mixed ownership reform at new era should be progressive and stable and should not be movable and radical privatization. Therefore, the model of the mixed ownership reform should be diversified, the reform that really embodies the original aspiration of the Party and suitability should be actively explored.