The invention discloses an oil cylinder controlled brake mechanism, which comprises a brake oil cylinder, connecting pins, connecting steel structures and brake blocks, wherein the brake oil cylinder consists of a cylinder barrel and a piston rod and a restoring spring which are arranged in the cylinder barrel; the restoring spring presses against the upper end of the piston rod in the upper part of the cylinder barrel; the upper part of each connecting steel structure is connected with the cylinder barrel, and a chute is formed on the lower part of each connecting steel structure; the brake blocks can vertically slide in the chutes; and the connecting pins are clamped in the brake blocks and connected with the lower end of the piston rod. The mechanism has the advantages that the piston rod moves vertically by controlling the oil inlet state of the brake oil cylinder, so that the connecting pins and the brake blocks are driven to move vertically, and functions of braking and unlocking are realized; the brake blocks can be detached and conveniently and directly replaced after being abraded, so the maintenance cost is low; and the mechanism can be fixed on different cars, so the mechanism is strong in universality.