With the development of new energy, large-scale wind power grid and photovoltaic bring challenges to the reliable operation of the system. Based on the actual situation, this paper introduces LOLP for evaluating the reliability of the system, analyzes the uncertain factors of the system after the new energy grid connected to the network, and models the uncertainties of the unit fault outage, the load forecast deviation, the wind power forecast deviation and the forecast photovoltaic deviation respectively. Based on considering the uncertainty factors, the optimization model of spinning reserve capacity considering the access of new energy is established. Taking the IEEE 39-bus standard test system as an example, the results show the reliability and economy of the proposed model, effectively optimize the allocation of spinning reserve capacity after new energy is connected to the network, and provide technical guidance for optimal scheduling of spinning reserve capacity.