During the braking process, when the electronic control device determines that the wheels tend to lock according to the wheel speed signal input by the wheel speed sensor, the ABS enters the anti-lock braking pressure adjustment process. For example, when the electronic control device determines that the right front wheel tends to lock, the electronic control device energizes the liquid inlet solenoid valve that controls the braking pressure of the right front wheel, so that the right front liquid solenoid valve is turned off, and the brake master cylinder output The brake fluid no longer enters the right front brake wheel cylinder, and the electronic control device turns off both the right forward fluid solenoid valve and the fluid outlet solenoid valve, turns the fluid inlet solenoid valve into an open state, and turns the fluid outlet solenoid valve into a closed state. At the same time, the electric pump is energized and operated, and the brake fluid is sent to the brake wheel cylinder. The brake fluid output by the brake master cylinder and the brake fluid pumped by the electric pump pass through the right forward fluid solenoid valve in the open state. Enter the right front brake wheel cylinder, so that the braking pressure of the right front brake wheel cylinder increases rapidly, and the right front wheel starts to decelerate and rotate again.