A dual-function antitheft lock belongs to a vehicle lock and comprises a lock shell, a lock core base, a lock core, a lock tongue, a number locking mechanism, a lock stem hinge base and a U-shaped lock stem; wherein, the lock shell is provided with a lock core base cavity, the top wall of the lock core base cavity is provided with a lock stem through hole, and the bottom wall thereof is provided with a key insertion slot hole, the middle of the lock shell forms a number lock slot cavity and the other end of the lock shell is provided with a lock stem base cavity; the lock core base is accommodated in the lock core base cavity; the lock core is arranged on a lock core base; the lock tongue is arranged in a lock tongue slot, an eccentric head slot is machined on the lock tongue, one end of the lock tongue slot is provided with a lock stem insertion hole and the other end thereof is provided with a key slot and a lock shaft hole, and one end of the lock tongue is provided with a lock shaft brake flange; the number locking mechanism is arranged in the number lock slot cavity; the lock stem hinge base is arranged in the lock stem base cavity; one end of the U-shaped lock stem is assembled with the lock stem insertion hole through insertion and the other end is hinged with the lock stem hinge base. The dual-function antitheft lock enables the lock core to be in effective protection state, has ideal safety and protection effects, has simple structure, ensures the code to be adjusted and changed by vehicle owners as needed.