A car lock structure built in an automatic transmission shift rod having a latching opening and a latching hole on the push rod and the push rod tube respectively, a lock cylinder and a latching board formed by the lock bracket at a position corresponding to the latching opening and the latching hole, such that when the lock cylinder is turned, the latching board will latch into the latch hole of the push rod tube and the latching opening of the push rod to form a mutually latch structure among the push rod, the push rod tube, and the lock cylinder, and the push rod is restricted and not able to move downward due to the latching effect of the latch opening.