The invention discloses an automobile start controlling and protecting method based on a CAN bus. According to the automobile start controlling and protecting method based on the CAN bus, a CAN bus module and a CAN bus combination instrument communicate through a CAN protocol; signals of an ACC gear, an ON gear and an ST gear of an ignition switch are input to the CAN bus combination instrument; a main power switch, a start relay, a start main power switch and an ON gear power control terminal of an engine ECU are connected into the CAN bus module and controlled by the CAN bus module; gear signals of a neutral position switch and a hatch gate switch are input into the CAN bus module; and according to the defined Start Control and Protection Logic Relationship Table, a logic control program is written on the basis of complying with the SAE J1939 protocol. By the adoption of the automobile start controlling and protecting method based on the CAN bus, through the superior start protection strategy and reasonable setting of time and the logic relationship control, all devices of a start system are protected to the greatest extent; and meanwhile, the safety of the whole automobile is improved, the service life of an automobile engine is prolonged, and the maintenance cost of the automobile is lowered.