Hydrogen leakage monitoring system, vehicle using the same and hydrogen leakage monitoring method using the same

A hydrogen leakage monitoring system is disposed on a vehicle body of a vehicle. The hydrogen leakage monitoring system includes a speed sensor, an inclination sensor, a hydrogen concentration sensor and a processor. The speed sensor is configured to sense a vehicle speed. The inclination sensor is configured to sense an inclination angle of the vehicle body. The hydrogen concentration sensor is configured to sense an actual hydrogen leakage value of a hydrogen device. The processor is configured to obtain the inclination degree value according to the vehicle speed and the inclination angle, obtain a hydrogen leakage threshold according to the inclination degree value, and initiate a corresponding process based on the actual hydrogen leakage value being greater than the hydrogen leakage threshold.