To investigate the coupling mechanism between proton exchange membrane fuel cell (PEMFC) and high-temperature heat pump (HTHP), and to study the influence of PEMFC operating parameters on the operational stability of a HTHP steam system, a co-simulation model of a HTHP steam system coupled with fuel cell waste heat is established based on Python and Modelica, which recovers fuel cell waste heat and produces steam at 120 ℃. Firstly, this paper analyzes the electric power, heat output and electrical efficiency of PEMFC under different current densities, operating pressures and operating temperatures, as well as the influences of key parameters of the heat pump. The simulation results show that under a single fluctuating factor, the heat pump coefficient of performance (COP) is most sensitive to fluctuations in the cell operating temperature, followed by the current density, while the cell operating pressure has the lowest sensitivity. Furthermore, for the heat source fluctuation caused by step changes in the fuel cell current density, a proportional-integral-derivative (PID) control strategy can be applied to regulate the superheat at the heat pump compressor inlet and the compressor frequency. After the implementation of the control strategy, the steam output of the HTHP steam system increases by an average of 12.47 kg/h compared with the uncontrolled system. This combined heat and power system can provide guidance for the coupling mechanism between PEMFC and HTHP. However, the influence of simultaneous multi-parameter disturbances of the PEMFC on the HTHP still requires further investigation.