Hydroelectric generator

The utility model discloses a hydroelectric generator comprising a buoy and generator sets, the buoy is connected with external rotating wheels of the generator sets through ropes, two identical generator set structures are disposed oppositely, a water shield is disposed outside each generator set, the external rotating wheels are driven to rotate by the buoy through the ropes, generators are driven to generate electricity, and each generator set is also equipped with a spiral elastic device and the generator. When the hydroelectric generator is put into a river, potential energy of the spiral elastic devices are changed by utilization of changes of water flow velocity to drive the generators to generate electricity; and when the hydroelectric generator is put into a shallow sea, electricity can also be generated by utilization of seawater reciprocation besides the above power generation mode. The buoy can also be used as a navigation mark lamp after being modified. Water flow energy is converted into electri