The invention relates to a braking method of an electronic parking braking system, the electronic parking braking system and a vehicle. The braking method includes the steps that when a first wheel speed sensor of a wheel loses efficacy, a wheel speed signal is acquired from a second wheel speed sensor, which normally works, of the wheel, and wheel speed signals of other wheels of the vehicle are acquired; the slip rate of each wheel is acquired according to the wheel speed signals of the wheels; and the clamping force of brake calipers of the wheels is adjusted if the slip rate of the wheels is not within a preset range, so that the slip rate of the wheels is adjusted to be within the preset range. By means of the braking method, the vehicle is kept stable in dynamic braking, and the phenomenon that the vehicle is out of control in the braking process is effectively prevented.