The invention relates to a wheel-side reducer with a brake for a bracket carrier which mainly comprises the brake, a double-planet reducer, a brake shell body, a brake shell, an inner bracket, a braking spring, a friction plate, a bearing, a spline shaft sleeve, a stop block, a distance sleeve, a round nut, an internal annular gear, an end cover gear ring, planet gears, a sun gear, an air permeable cap, an oil drain plug, an oil filling hole and a fixing block. An output end of a travelling mechanism adopts a brake plus reducer integrated design, the brake adopts totally closed wet-type braking, a spring ring comprises 30 small springs, the ring friction plate comprises 8 static friction plates and 9 dynamic friction plates, integral braking and hydraulic releasing are carried out, the spline shaft sleeve and the double-planet reducer are connected, the reduction is realized by a first-grade planet gear and a second-grade planet gear, the transmission speed ratio is 40 to 1, and the reducer and a travelling wheel are connected, thus driving the whole vehicle to run. The device has advanced design, compact structure, small volume, good heat dissipation, steady running and safe and reliable properties.