The CEL-PCRD300-12 photochemical reaction instrument (LED) mainly uses the screening of catalysts to improve the efficiency of photocatalytic experiments. It can simultaneously experiment with 12 samples, which realizes the analysis of samples under different wavelengths and different conditions and speeds up the experimental process. The functions of temperature control, ventilation, vacuum, stirring, and selection of various wavelengths of the catalytic reaction tube are realized. The standard GDT-12 gas distributor can also independently control the experimental reaction atmosphere of the reaction tube.