The invention belongs to a weight device, in particular to a weight exchanging rotary table with a speed change function. The weight exchanging rotary device comprises a rotary shaft, wherein a rotary table is arranged on the rotary shaft; the rotary table is provided with a first position locating mark and a second position locating mark; the rotary shaft is connected with a torque motor; the torque motor is respectively connected with a first direct current power supply and a second direct current power supply; and the rotary table is also provided with a photoelectric sensor. The weight exchanging rotary table can effectively reduce the impact on the rotary shaft when the rotary table stops, enhances the locating stopping precision, ensures that weights can return the initial positions after the weights are subject to the second exchange, and can prolong the service life of the rotary shaft.