Abstract: To examine how surface microtexture and operating parameters affect the sealing performance of proton exchange membrane fuel cell, using fractal theory to quantify seal surface morphology, and using fractal dimension D and scale coefficient G to characterize surface complexity and multiscale features, a 2D sealing model integrating microtexture was developed. Gas leakage rates were calculated using Poiseuille theory and Roth model, and model accuracy was verified through experiments. Results reveal increasing fractal dimension D raised hydrogen leakage rates, while higher scale coefficient G reduced hydrogen leakage. Below 0.4 MPa compression pressure, surface morphology controlled leakage behavior. Above 0.4 MPa, sealing performance stabilized. Surface microtexture optimization proved critical under low clamping pressures, whereas combined control of operational parameters became essential under high clamping pressures. These findings provide theoretical reference for engineering seal designs.