It is an urgent need to improve the peak shaving and frequency regulation capacity of thermal power plants to build a new power system in China. Using industrial steam heat storage network is expected to improve the frequency regulation performance of combined heat and power units. In this paper, the dynamic model of steam heating network is established by using GSE software, and the dynamic characteristics of steam pressure, energy storage and output power in steam heating network during auxiliary frequency regulation are studied. The results show that the maximum continuous frequency regulation time of the steam heating network of the research object is 400 s, the maximum power increment of the unit is 33 MW when the heating steam valve is closed, and 1111 MWh additional electricity can be obtained by closing the valve for five consecutive times.