The invention discloses a preparation method of 2-chloro-1,1,1-trialkoxy ethane. The current preparation methods have the disadvantages of environmental unfriendliness, high production cost and low yield. According to the invention, a polar solvent is taken as a reaction medium and a catalyst, chlorosuccinimide is taken as a chlorinated reagent, and is reacted with trialkoxy orthoacetate to prepare 2-chloro-1,1,1-trialkoxy ethane at the temperature of -20 DEG C-150 DEG C; after finishing the reaction, succimide is removed through crystallization and filtering, and then 2-chloro-1,1,1-trialkoxy ethane can be obtained through vacuum rectification and purification. The method provided by the invention has small pressure on environmental protection, no waste is generated; the selectivity of a reaction system reaches as high as 95%, the content of the product can reach as high as 99%, the dichloro by-product is greatly reduced, and the method is an environment-friendly type production technology suitable for industrial production with characteristics of economy and safety.