The invention discloses an anti-theft system of an automobile door, relating to the field of the automobile anti-theft technical problem. The anti-theft system of the automobile door comprises a coded lock and an ECU (Electronic Control Unit), wherein the coded lock is mounted on the door; and the ECU is used for receiving a code input from the coded lock, locking an engine fuel supply system if a wrong code is input and unlocking the engine fuel supply system and the door if a correct code is input, and further an ECU locking instruction and an alarm instruction are sent if the times of continuously inputting wrong codes exceed the predetermined times. Due to the design, a thief can not drive away an automobile due to locking of the engine fuel supply system even though the thief forcedly enters the automobile by prying the door or in other ways in the case of inputting wrong codes or having no code input; and therefore, the security of the whole automobile is improved.