On the basis of CMM model, with China's rural financial running data from 1978 to 2013 as the research object, this paper constructs the rural financial maturity model to measure and analyze the development of China's rural finance since the reform and opening-up. The results show that the rural financial maturity in China has maintained an upward trend and accelerates after 2007, but there are fluctuations. The contribution of scale, structure and efficiency to China's rural financial maturity differs a lot, and among them scale dimension plays a key role, which highlights that the features of coordinate development at all levels are ignored during the development of China's rural finance.