Door lock

The utility model discloses a door lock. The anti-theft door lock comprises a lock shell arranged on a door plate and a lock cylinder arranged in the door plate. A lock shell cover is arranged on thelock shell; the anti-theft lock is characterized in that a first sliding groove is formed in the lock shell, a key hole corresponding to a lock hole of the lock cylinder is formed in the inner wall ofthe first sliding groove, a dustproof cover in sliding fit with the first sliding groove is arranged in the first sliding groove, an opening matched with the dustproof cover is formed in the lock shell cover, and a reset spring is arranged between the dustproof cover and the inner wall of the first sliding groove in an abutting mode; the key lock has the advantages that the dustproof cover is arranged on the lock shell, when the key is not used for opening a door at ordinary times, the dustproof cover is in a closed state, dust can be effectively prevented from entering the lock cylinder, thekey lock is better protect