Evaporative emission monitoring method and system

The present disclosure relates to an evaporative emission monitoring method and system for monitoring an evaporative emission system of a vehicle, characterized in that the method comprises the steps of: stalling an engine of the vehicle and keeping a canister vent valve of a canister open; closing the carbon tank ventilation valve and a switch valve of the evaporative emission system, opening a carbon tank flushing valve of the carbon tank, and monitoring a pressure value delta P1 of the evaporative emission system; the carbon tank ventilation valve is opened again for ventilation for a period of time, the carbon tank ventilation valve is closed again, and the pressure value delta P2 of the evaporative emission system is monitored; the sum sigma P total of the pressure value delta P1 and the pressure value delta P2 of the evaporative emission system and the threshold value pressure value P threshold value of the evaporative emission system are calculated, and if sigma P total is larger than or equal to P thr