The invention discloses a trigger and a method and device for determining the output state of a trigger. The method comprises: a switch quantity signal transmitted by a setting input terminal of a trigger is received; the received switch quantity signal is processed according to a preset logic to obtain an output signal; the output signal is transmitted to a current value port, wherein the currentvalue port is used for outputting a numerical value corresponding to the output signal and the output signal is outputted by a first output terminal; and according to the numerical value, the outputstate of the trigger is determined. Therefore, a technical problem that the trigger has the potential safety hazard in interlocking protection according to related techniques is solved.