The invention discloses a brake pedal freely adjustable in height and force exertion area. The brake pedal comprises a brake pedal body, a connecting arm, a threaded pin, a power line, a base steel plate, a first miniature electric telescopic rod, a pedal box, a first steel plate, a second steel plate, a third steel plate, a fourth steel plate, a telescopic rod placement box, second miniature electric telescopic rods, a control box and an anti-slip nail, wherein the brake pedal body is welded on the connecting arm, the control box and the power line are arranged on the connecting arm, the connecting arm is connected with a braking system through the threaded pin, a base steel plate is arranged at the bottom end of the brake pedal body, the first miniature electric telescopic rod is arranged at the top end of the base steel plate, the pedal box is arranged at the top end of the first miniature electric telescopic rod, the telescopic rod placement box is arranged in the pedal box, and a plurality of second miniature electric telescopic rods are arranged on the telescopic rod placement box. The device adapts to feet different in size, does not bring discomfort to people in use and brings convenience to the people in operation, and the safety performance is improved.