The invention provides a stabilizer for tetrachloroethylene. The stabilizer comprises the following material components: triethanolamine, n-pentane, butylene chlorohydrin, oxybutylene and thymol. The invention further provides a preparation method of the stabilizer. The stabilizer prepared according to the invention is applied to tetrachloroethylene production; after the stabilizer is added in the tetrachloroethylene, the quality indexes of the tetrachloroethylene are as follow: purity 99.9,615-99.9,918%, pH 9.62-9.75, moisture content 16-18 ppm and chrominance 10; and 360 days later, the purity change rate of the tetrachloroethylene is 0-0.038%, the pH change rate of the tetrachloroethylene is 0.1-0.2%, and the moisture content and the chrominance of the tetrachloroethylene do not change. The stabilizer prepared according to the invention is used for tetrachloroethylene, achieves a service life of two years, has good thermal stability and good moisture resistance, and cannot corrode cleaning equipment and workpieces.