The invention provides a waterproof connection structure of a solar power generation device comprising a plurality of bearing units, a plurality of power generation units, a plurality of water blocking units, and a plurality of second fixing units. The bearing units respectively include two first grooves, a second groove positioned between the first grooves, and two bearing surfaces between the first grooves and the second groove. The power generation units respectively include a first fixing unit for accommodating a solar panel element, and each of the first fixing units is provided with a connection surface at a side facing to the bearing surfaces. The water blocking units are arranged between the connection surfaces and the corresponding bearing surfaces. The second fixing units are assembled on the second grooves. First containers for accommodating the water blocking units are respectively provided at the bearing surfaces corresponding to the connection surfaces.