The mesoporous molecular sieve (MCM)-41 using ionic liquid as template has been prepared. The typical template of ionic liquid was [C(16)mim]X. In this article, the use of 1-alkyl-3-methylimidazolium ([C(n)mim]Br, where n=12,14,16,18,20) salts as templates in the synthesis of MCM-41 is reported. The results showed that the synthesized MCM-41 had uniform pore diameter, high surface area and stable framework. The largest surface area of MCM-41 was the one prepared with [C(14)mim]Br as template. When using [C(18)min]Br as template, the narrowest pore distribution sample was obtained and the effect of surface tension of template solution to MCM-41 was first discussed.