The invention provides a blocking force control method and system of a braking system. The blocking force control method includes injecting brake liquid by the braking system, and applying a first action force to a brake pedal so as to enable a brake caliper of a brake on a left or right wheel to move to the initial position contacting with the brake disc; keeping the first action force constant so as to pull up a parking brake handle by a second action force to tension a parking brake cable without generating brake force of the brake, and locking the parking brake cable; keeping the second action force constant, setting a vehicle on a brake detection platform, and driving wheels to rotate so as to eliminate burrs of the brake disc by means of a drum. The blocking force control method of the braking system can avoid unequal blocking forces of the wheels and avoid depot repair or reworking due to overhigh blocking force of the wheels, and thus assembly efficiency and quality of finished vehicles are improved.