The main principles of this technology are as follows: high-energy light waves are used to irradiate pollutants to directly participate in the photolysis reaction; Or use this light wave to excite the semiconductor catalyst to make it have the ability of redox reaction, so as to achieve the purpose of oxidative degradation of pollutants; Or through the absorption of high-energy photons by plants, biological effects and chemical effects are produced, and the organic matter is degraded. Photocatalytic degradation of environmental pollutants is characterized by simple equipment, operation at normal temperature and pressure, rapid and complete degradation of organic matter and no secondary pollution. The degradation rate of several kinds of dye wastewater below 1mg/l is 95-1% under normal temperature and pressure by using low-pressure mercury lamp as light source for 2 minutes. The pesticide residues of ginseng containing .817mg/kg of hexachlorobenzene and .911mg/kg of pentachloronitrobenzene were degraded after 4 hours of operation, and the degradation rates were 93% and 97% respectively.