Under the background of carbon neutralization, developing the multi-energy system (MES), which effectively integrates kinds of energy resources, is one of the keys to solving the environmental contradiction. At present, considering heat storage, the research on the optimal scheduling of MES, especially industrial park MES, focuses on the heat storage tank. The potential of the heating supply network (HSN) for heat storage is underestimated and its operational constraints haven’t been fully studied. Therefore, with consideration of quantitative heat storage in HSN, a day-ahead operation scheduling optimization model for MES is proposed. The model proposes a tubular heat storage body (THSB) to describe the heat storage characteristics and charge/discharge constraints of HSN and studies its impact on economic benefits and stability of output power. Equivalent method is used to quantify the heat storage capacity of HSN. Based on the established model, we take a real industrial park to optimize the operation plan of heating conditions in winter. Results indicate that the optimized scenario shows better economic benefits and output stability, which saves 1,303 yuan of operation cost per day.