The chloromethylation of 2-chloro-thiophene and paraformaldehyde to 2-chloro-3-chloromethyl-thiophene in the catalysis of different ionic liquids，[C2mim]Br，[C3mim]Br，[C4mim]Br，[C5mim]Br，[C6mim]Br，[C7mim]Br，[C8mim]Br，[C12mim]Br，[Bmim]PF6，[Bmim]BF4，[Bmim]C4F9SO3 and [Bmim]Cl was studied. The result showed that as a phase transfer catalyst ionic liquid could promote the chloromethylation of 2-chloro-thiophene. [C4mim]Br and [C8mim]Br had best catalytic activities. The influence factors, such as the dosage of catalyst, reaction temperature, reaction time and the amount of paraformaldehyde were discussed. Under the best conditions, the dosage of catalyst [C8mim]Br was 5%, 40癈, 8h, good yield was got in 92.1%. The chloromethylation of 2-chloro-thiophene promoted by ionic liquids is with the characteristic of few catalyst, high yield and easy products separation.