Automobile integrated brake-by-wire system

The utility model relates to a brake system, and in particular relates to an automobile integrated brake-by-wire system. The automobile integrated brake-by-wire system comprises a brake fluid tank, a motor, a plunger pump, an electronic control unit, a brake pedal and a wheel brake, and is characterized by further comprising a step-shaped main cylinder and an I-shaped piston, wherein the step-shaped main cylinder is separated into a large hole diameter cylinder body and a small hole diameter cylinder body, and the large hole diameter cylinder body is provided with a small oil hole; the I-shaped piston comprises a large piston, a small piston and a piston connecting rod, the large piston is connected to the small piston by the piston connecting rod, the large piston is provided with a seal ring, and the small oil hole is positioned adjacent to the initial position of the large piston. According to the automobile integrated brake-by-wire system, processing difficulty of the main cylinder can be reduced, precision of the inner hole of the main cylinder is ensured, and meanwhile reliability of a standby brake can be improved, and thereby the standby brake is not limited.