With the reform of the electricity market, the coupling interaction between different stakeholders becomes increasingly more obvious. This paper proposes a multi-time-scale optimal scheduling model for park-specific integrated energy system operator (IESO) considering the Stackelberg game given the different interest demands of different subjects in the park-specific integrated energy system (IES) and the accuracy of source-load forecasting. Firstly, a day-ahead Stackelberg game model is established with the park-specific IESO as the leader and the park users as followers. Afterward, taking into account the influence of large errors in source-load forecasts, an intraday dispatch model and a real-time correction model based on model predictive control were established. Through the analysis of calculation examples, it is verified that the multi-time scale optimal scheduling of park-specific IESO which considers the Stackelberg game can effectively reduce system operating costs, improve system economy, and stabilize fluctuations caused by source-load forecast errors.