Back locking method of door lock

The invention discloses a back locking method of a door lock. A first sensor is arranged in a lock body of the door lock and is used for detecting stretching or contracting motion of a locking component in the door lock and also used for generating a first feedback signal, a second sensor is arranged in the lock body of the door lock and is used for detecting rotating motion of a handle outside a door and generating a second feedback signal; a control module receives the first feedback signal and the second feedback signal; when a handle in the door is rotated to drive a main transmission mechanism to drive the locking component to stretch out, the first feedback signal is sent to the control module by the first sensor, and it is affirmed by the control module that the motion is back locking motion; afterwards, when the locking component is driven by the handle outside the door to rotate in the contracting direction, the first feedback signal is sent to the control module by the first sensor, the control module controls a clutch to be in disengagement state, the locking component is static at the moment, and it is affirmed by the control module that the motion is motion preventing back locking releasing. By means of the back locking method, back locking and back locking releasing can be easily, quickly and conveniently achieved.