The efficient and safe synthesis of chlorides is attractive in pharmaceutical chemicals yet presents challenges. Herein, a novel route has been developed for the conversion of alcohols into the corresponding alkyl chlorides in continuous flow microreactor. Meanwhile, the system utilizes deep eutectic solvents (DESs) hydrochloride solutions (DESs/HCl) as both solvents and catalysts for this reaction. The results suggest that the premixed mode continuous flow microreactor using DESs/HCl can significantly improve the harsh reaction conditions in the synthesis reaction of chlorides. Furthermore, tuning the HCl concentration under 383 K and 30 min conditions significantly increased the yields of n-Butanol chloride and Benzyl chloride to 86 % and 98 %, respectively. This work shows the great application potential of the continuous flow microreactor combined with DESs/HCl to convert alcohols into corresponding alkyl chlorides or aryl chlorides. Besides, the fluid model and HCl absorption kinetics were established based on the calculated diffusion coefficients (DR), Damköhler number (Da), Bodenstein number (Bo), residence time (τ), and experimental results. The flow model of the mixture of DESs/HCl and alcohols in the microreactor was a plug flow, which is beneficial for improving the efficiency of this reaction.