Abstract: In order to realize the economic and flexible operation of renewable energy power system and the global optimality allocation of generation resources, a novel monthly security-constrained unit commitment which considers the hierarchical relationship between monthly unit commitment and short-term scheduling, was presented in this paper. Firstly, by taking the probability information of short-term randomness uncertainty and long-term correlation uncertainty characteristic of renewable energy into account, a simulation method of renewable output based on the non-parametric kernel density estimation（N-KDE） and ARMA regression analysis was put forward. On this basis, a stochastic scenario based monthly unit commitment coordinating short-term scheduling was constructed. Secondly, in response to the computational intractable of the proposed model, both of the constrained transformation and relaxation induction technology were employed to provide an improved solving strategy according to the popular branch and bound principle. Finally, the result of the actual system shows the validity and advantage of the presented model and solution method.