Locking device for rear fence door of livestock and poultry car

The invention discloses a livestock and poultry car rear fence door locking device which comprises a fixing base fixed to a tail plate and a lock pin movably connected to a rear fence door, the lock pin comprises a vertically-arranged lock rod, a lock handle and a transverse pin, the lock handle and the transverse pin are fixedly arranged on the lock rod, the transverse pin perpendicular to the lock rod is clamped with the fixing base, and a long hole where the transverse pin is inserted is formed in the fixing base; a rotating seat for inserting the lock rod is fixed on the rear fence door, the lock rod is sleeved with a return spring, and the two ends of the return spring abut against limiting structures on the rotating seat and the lock rod respectively; a clamping pin facing the same direction as the transverse pin is arranged on the lock rod, a limiting plate flatly attached to the door face is installed on the rear fence door, two limiting grooves clamped into the clamping pin are horizontally formed in