Abstract: In an attempt to assess the stability of ＂Sanhuanglian＂ mixture and to provide necessary information for the application, production, packaging, storage and transportation of new veterinary drugs, on the basis of quality standards for ＂Sanhuanglian＂ mixture, the effects of temperature, humidity and illumination on the physical and chemical properties of the preparation were examined by light accelerate experiment and accelerate experiment. The active constituents of ＂Sanhuanglian＂ mixture, baicalin and forsythin, were qualitatively identified by thin-layer chromatography. Futhermore, the pH value, relative density and active ingredient content were also measured by light accelerate experiment and accelerate experiment. The results showed that within the specified time, the ＂Sanhuanglian＂ mixture exhibited the same color spots on the corresponding positions of each reference substance; the pH value, relative density and effective ingredient content all met the requirements; the ＂Sanhuanglian＂ mixture was not sensitive to light, and it was not necessary to consider avoiding light during production, storage and transportation and it could be packaged in a transparent container.