The classification of fuel cell humidifier and the current research status at home and abroad were introduced, and orthogonal experiments were designed to investigate the influence law and the degree of influence of fluid parameters on the thermal mass transfer characteristics of porous carbon plate humidifier. The results show that the humidity of the fluid inlet on the high-temperature side is the main factor affecting the thermal mass transfer characteristics of the porous carbon plate humidifier, followed by the fluid flow rate and the fluid inlet temperature on the high-temperature side. Therefore, the influence of high-temperature side fluid inlet humidity should be prioritized when designing the humidifier. Meanwhile, for different fuel cell systems and operating conditions, the thermal mass transfer performance of the porous carbon plate humidifier can be optimized by adjusting the fluid flow rate and high-temperature side fluid inlet temperature to improve the efficiency and service life of the fuel cell system.