According to a loading device for fitness equipment counterweights, a low-position counterweight plate, a middle counterweight plate and a high-position counterweight plate are sequentially overlaid above a base plate and guided by a guiding rod, connecting holes are machined in the two sides of the low-position counterweight plate, the middle counterweight plate and the high-position counterweight plate correspondingly, and the high-position counterweight plate is fixedly connected with a stretching flange. Counterweight connecting mechanisms are located on the two sides of a base and comprise power gears and racks, wherein the power gears and the racks are engaged. A working frame is fixed to the inner sides of the racks, and electromagnetic attraction units are fixedly arranged on the inner side of the working frame. Door-type connecting pieces are arranged on the electromagnetic attraction units in an attracted mode, and each electromagnetic attraction unit is electrically connected with a control panel through a wire. During training, the power gears act to feed the electromagnetic attraction units inwards, the door-type connecting pieces are inserted into the connecting holes, after an athlete selects the corresponding weights through the control panel, corresponding electromagnets stop working, and after the other door-type connecting pieces exit, the athlete can conductstretching training. The loading device is compact in structure, capable of being automatically adjusted, convenient, rapid, safe and reliable.