The solvent-free synthesis process of 2-chloroethyl ethyl ether was improved. Using triethylamine as the catalyst for the reaction of 2-ethoxyethanol with thionyl chloride, the obtained product was washed with saturated sodium bicarbonate solution, saturated sodium chloride solution and dried with anhydrous sodium sulfate to obtain 2-chloroethyl ethyl ether. The structure of product was characterized by 1H-NMR and GC-MS. The effects of molar ratio of reactants, reaction temperature and reaction time on the chromatographic purity and yield of the product were investigated by one-variable at-a-time optimization approach. After optimization, the molar ratio of 2-ethoxyethanol : thionyl chloride : triethylamine was set to 1.0 : 1.3 : 0.3, the reaction temperature was 70 °C, and the reaction time was 4 h. Under this process, the product yield over 90.2% and the chromatographic purity over 99.4%，the assay over 99.2% were obtained after pilot-scale amplification of kilograms.