The invention discloses an antitheft pedal lock for a car, and the antitheft pedal lock comprises a clamp and a lock, wherein the clamp comprises a first clamping plate and a second clamping plate, and a clamping space is formed by the first clamping plate and the second clamping plate; the lock comprises a lock body, and a lock head, a lock bolt and a lock pin, which are installed inside the lock body, the lock body is connected onto the first clamping plate in a longitudinal sliding way, and the first clamping plate is provided with a plurality of toothed grooves at intervals which are matched with the lock pin in the longitudinal direction; and the lock head controls the lock pin and the lock bolt to move in the transverse direction, when the antitheft pedal lock is locked, the lock bolt stretches into the clamping space, and the lock body slides into the toothed groove of the corresponding height along the longitudinal direction of the first clamping plate. The lock body can be connected onto the clamp in a longitudinal sliding way, the clamp is combined with the lock, so that the storage problem caused by separation of the clamp and the lock can be solved; and the toothed groove positioning way is used for substituting the traditional through-hole positioning way, so that more precision in height adjustment and positioning control can be achieved.