The invention relates to a controllable vacuum booster which is provided with a booster body (1), and the booster body (1) comprises a front cavity (2), a back cavity (3) and a mounting bolt (7) positioned on a shell of the back cavity, wherein the front cavity is internally provided with a braking master cylinder piston (4); a booster membrane (5) is arranged between the front cavity (2) and theback cavity (3); and the braking master cylinder piston (4) positioned in the front cavity is provided with a tappet rod (6). The controllable vacuum booster is characterized in that the mounting bolt(7) is connected with an air inlet electromagnetic valve (9) of the back cavity; and the tappet rod (6) is movably connected with an air inlet electromagnetic valve (8) of the front cavity. The controllable vacuum booster not only maintains a manual foot stepping brake mode so as to meet the requirement on normal brake operation of a driver, but also can automatically energize to carry out the brake operation under the conditions of tire burst, collision, or the like through the electromagnetic valve of the front cavity and the electromagnetic valve of the back cavity so as to reduce the traffic accident rate and improve the safety. The controllable vacuum booster has simple structure, low cost and convenient mounting process.