Abstract: Based on the features of extraction heating units that use adjusting butterfly valve to control extraction pressure for the regulation of heating extraction flow, and by analyzing the energy balance in extraction heating link of turbine, differential equations were constructed for simplified nonlinear dynamic model of the generating load-throttle pressure extraction pressure versus the fuel flow-opening of turbine governor valve-opening of adjusting butterfly valve. On above basis, the disturbance of generating load command, extraction pressure command and mass flow of circulating water in the heating network were simulated. Simulation results show that the relations between model inputs and ouputs are in accord with actual operation conditions of heating units, which can well explain the intrinsic mechanism by controlling extraction pressure to make the extraction flow follow the heating load demand.