The invention discloses a device and method for restoring a polluted water source through a multi-media bio-filter. The device is used for restoring polluted water of an upstream river way of a river type water source. A dam is arranged in the upstream river way. The device is arranged on the outer side of the dam. The device comprises a tower layer frame, carrier packing layers and a water collector. Water distributors are arranged at the upper end of the tower layer frame and used for introducing the polluted water source in the dam into the tower layer frame. The multiple carrier packing layers are arranged in the tower layer frame from top to bottom. The water collector is arranged at the lower end of the tower layer frame, collects the water source filtered through the carrier packing layers and drains the water source to a downstream river way. By the adoption of the device and method for restoring the polluted water source through the multi-media bio-filter, the water quality of the water source can be improved, the water body of the water source can be restored, the functions of the water source can be restored, and the safety of drinking water can be guaranteed.