The invention relates to a system for treating wastewater in the photovoltaic industry. The system comprises a regulating tank, an anaerobic biochemical tank, a sedimentation tank, a reaction tank anda mechanical stirring clarification tank, wherein the mechanical stirring clarification tank includes a first tank body, a mechanical stirring lifting system which is disposed on the first tank bodyand used for stirring the wastewater in the first tank body and a chemical supplying system which is used for supplying the wastewater in the first tank body with chemicals, and the mechanical stirring lifting system includes a stirring mechanism and a stirring motor which is used for providing power for rotary stirring of the stirring mechanism; the stirring mechanism can rotate so as to stir thewastewater and achieve circulation flow of the wastewater between a reaction chamber and a separation chamber, and a chemical supplying pipe communicates with the stirring mechanism; the mechanical stirring lifting system also includes a chemical spraying structure which is arranged on the stirring mechanism and used for spraying the chemicals provided by the chemical supplying system into the wastewater in the first tank body. Through the system for treating the wastewater in the photovoltaic industry, an effect of wastewater treatment is improved greatly, the efficiency of the wastewater treatment of enterprises is improved, and the productivity of the enterprises is improved.