Aiming at the problems of large reactor temperature fluctuation and slow response of thermal management subsystem in the load change process of hydrogen fuel cell engine system, a thermal management control strategy was proposed based on multi-parameter following of reactor power, coolant temperature difference between reactor inlet and outlet and coolant flow. A onedimensional simulation model of thermal management system was established using AMESim simulation software, and the simulation and analysis of different control strategies were conducted under typical operating conditions. The results show that the control strategies of the pump speed following the reactor power and the temperature difference between reactor inlet and outlet and the cooling fan speed following the outlet temperature of reactor and the coolant flow rate can effectively reduce the temperature fluctuation of reactor and improve the response speed of thermal management subsystem, which provides a solution to the control problem of hydrogen fuel cell engine system under variable load conditions.