The invention discloses a photovoltaic power generation device and a power generation method thereof, and belongs to the technical field of photovoltaic panels. The photovoltaic power generation device comprises a supporting base, an equipment box, a fixing frame and a photovoltaic panel body, the equipment box is fixedly connected to the upper end of the supporting base, the photovoltaic panel body is fixedly connected into the fixing frame, a driving speed reduction mechanism is connected into the equipment box, and the output end of the driving speed reduction mechanism is fixedly connectedwith a single-tooth gear. According to the invention, through arrangement of the driving speed reducing mechanism, the single-tooth gear, a first gear and a supporting plate, the photovoltaic panel body rotates along with the sun, so that the light receiving efficiency of the photovoltaic panel body is effectively improved; and through arrangement of a driving mechanism, a first bevel gear, a cylinder and a first reciprocating screw rod, the inclination angle of the photovoltaic panel body can be adjusted in real time according to the rising angle of the sun, so that the practicability of thedevice is effectively improved.