In order to adapt to complete opening to the outside world,China banking begin to introduce some strategic investors.The paper based on stochastic frontier function firstly makes an in-depth empirical study about cost ineffi- ciency of China major commercial banks and their strategic investors.The study finds that although not all the latter's cost inefficiency is worse than the former,the former should learn the advanced experience of controlling cost from the latter.In the period of the observation,state-owned banks and stock-holding banks constantly improve their ineffi- ciency.From the tendency of its change,the sample banks' efficiency will be convergent.