The fuel evaporation system is roughly composed of activated carbon canisters, drain control solenoid valves, fuel tank caps, steam separation valves, sensors and pipelines. The evaporation of gasoline at room temperature consists of two parts, fuel evaporative pollutants and refueling pollutants. Gasoline evaporative pollutants are recycled and reused through the EVAP system to meet the technical requirements of energy saving and environmental protection. No longer let these fuel vaporized pollutants be directly discharged into the atmosphere to pollute the air, but also can realize the reuse of waste, achieve the effect of energy saving and emission reduction.