The invention discloses an oil cylinder-propelled drum type braking force test device. A piston of a hydraulic oil cylinder of the test device is fixedly connected with one end of a rack, and the other end of the rack is engaged with a gear; a gear shaft passes through the gear; two braking and testing units are symmetrically connected with two ends of the gear shaft respectively, a first bearingand a bearing seat are arranged between each braking and testing unit and the outer end face of the gear respectively, the gear shaft passes through the first bearing and the bearing seat, and an anti-offset device is arranged beside the rack; each braking and testing unit comprises a torque sensor, a first drum and a second drum; a second bearing and a bearing seat are arranged at two ends of the rotating shafts of the first drum and the second drum respectively; and one end of the rotating shaft of the first drum is connected with one end of the torque sensor, and the other end of the torque sensor is connected with the gear shaft. The test device has the advantages of high measurement precision, small error and capability of performing mobile test.