To alleviate environmental problems, natural gas is gradually replacing fossil fuels, which makes the electricity and natural gas system important. However, there are many uncertain factors in the electricity and natural gas system. In this paper, these uncertainties such as wind power, electric loads and natural gas loads are analyzed based on scenario analysis. Further, in order to obtain the optimal economy, the unit commitment are determined first and then the day-ahead scheduling model is established. Testing results verify the effectiveness of the proposed method.