The invention discloses a high-practicability unreeling braking device for a steel belt. The high-practicability unreeling braking device comprises a bottom plate, wherein an upper surface of the bottom plate is fixedly connected with surfaces of two bearings respectively through two supporting rods; rotary shafts are arranged in the two bearings in a sleeving manner; one opposite end of the two rotary shafts is fixedly connected with two side faces of an unreeling roller; a steel belt roll is arranged on the surface of the unreeling roller; and a first braking device and a second braking device are arranged on the surface of the bottom plate. According to the high-practicability unreeling braking device for the steel belt, the first braking device and the second braking device are arranged; when the unreeling roller needs to be stopped, two electric push rods are stretched and rubber strips arranged on inclined planes of two clamping plates and a lug boss arranged in an annular groove are squeezed and a relatively large friction force is generated by the rubber strips and the lug boss; and the first braking device and the second braking device are used for braking at the same time, so that the braking effect of the unreeling roller is better and the reeling/unreeling speed of the unreeling roller is controlled better.