The invention discloses a wheelchair brake system which comprises an upper shell, a lower shell and a brake device, the upper shell comprises an upper shell bottom plate, the two sides of the upper shell bottom plate are each provided with an upper shell side plate, and the upper shell side plates are each provided with a through sliding notch; the lower shell is rotatably connected with the upper shell, the lower shell comprises a lower shell bottom plate, two sides of the lower shell bottom plate are respectively provided with a lower shell side plate, and each lower shell side plate is provided with an inclined locking bayonet; the traction assembly is arranged between the upper shell and the lower shell in a turnover manner, and the traction assembly comprises a sliding screw rod; wherein the lower shell is located between an opening position and a closing position, and when the lower shell is located at the closing position, the sliding screw penetrates through the sliding notch and the locking bayonet at the same time. Due to the adoption of the pedal-controlled parking structure, the parking device is convenient to mount, simple to operate, safe and reliable.