The utility model provides a cable pay-off drum with a sliding block type brake device. The cable pay-off drum with the sliding block type brake device aims to solve the problem in the prior art that the a pay-off drum stops rotating via an iron rod, so that potential safety hazards exist, and comprises a pedestal, a rotating shaft, a lower drum body and brake blocks. The rotating shaft is vertical and is in adapting connection with the pedestal, and the left and right sides of the pedestal are equipped with the side chutes respectively. A side sliding block is fixedly connected with the lower end of each brake block, and the two side sliding blocks are arranged in the two side chutes respectively. The front side of the pedestal is equipped with a front chute in which a front sliding block is arranged, and the front sliding block is connected with a driving device. Two connecting rods are in adapting connection on the front sliding block, and the back ends of the two connecting rods are in adapting connection on the two brake blocks respectively. According to the utility model, the driving device controls the two brake blocks to move via the two connecting rods, so that the two brake blocks clamp the rotating drum body to stop the drum body via the friction forces. The cable pay-off drum with sliding block type brake device is safe and reliable, is high in working efficiency, and effectively prevents a conducting wire from going forward continuously and becoming disordered.