To address the issue of insufficient grid support when proton exchange membrane fuel cells (PEMFC) are integrated with the grid using maximum power point tracking (MPPT) or constant power control, this paper proposes a frequency regulation strategy based on adaptive power tracking control for PEMFC. First, considering the relationship between frequency and power as well as the inherent characteristics of PEMFC, a droop-based active power-frequency control method with self-adjusting droop coefficient is proposed. Second, an adaptive power tracking control algorithm is developed based on the principle of disturbance observer, enabling PEMFC to dynamically regulate its output power to support system frequency. Finally, considering the maximum power point characteristic of the PEMFC, its operating point is constrained to avoid operation in the concentration polarization region—this would otherwise lead to significant energy waste and shorten the service life of the PEMFC. A model is built on the MATLAB/Simulink simulation platform to verify the effectiveness of the proposed control strategy. Results show that compared with the fixed droop coefficient control, the proposed control strategy reduces the system’s frequency peak value by 0.02 Hz and frequency valley value by 0.03 Hz, respectively.