The invention provides a method and a system for detecting person trapping in an elevator. According to the logic combination between multiple outputted detection signals of the elevator from an elevator controller, the person trapping state of the elevator is detected. The detection signals comprise a person carrying signal, a door lock signal, a fault signal and an overhauling signal; when the person trapping state is determined, a corresponding alarming signal can be sent out. The method and the system have the advantage that the problem of false judging on person trapping in the elevator can be effectively solved.