Belt pulley capable of preventing belt from being separated

The belt pulley capable of preventing the belt from disengaging comprises a pulley body, the surfaces of the two sides of the pulley body are both fixedly connected with rotating rods, the side surfaces of the rotating rods are connected with combining shafts, and the positions, located on the two sides of the pulley body, of the upper surfaces of the combining shafts are fixedly connected with connecting rods. A limiting plate is fixedly connected to the end, away from the closing shaft, of the connecting rod, a first ball is movably connected to the interior of the limiting plate, a groove is formed in the side surface of the wheel body, an adjusting ring is movably connected to the interior of the groove, and a splicing plate is slidably connected to the side surface of the adjusting ring. According to the belt pulley, the adjusting ring and the spring are installed, the adjusting ring is pressed towards the interior of the pulley body, the adjusting ring can extrude the spring, the diameter of the pulley