A stable mesoporous aluminosilicate with hexagonal symmetry (MAS-5) has been synthesized by the co-templates of tetraethylammonium hydroxide (TEAOH) and cetyltrimethylammonium bromide (CTAB) cationic surfactant. The cracking of 1,3,5-triisopropylbenzene is used as probe reaction to test its catalytic properties. Catalytic data show that the conversion over the stable mesoporous aluminosilicate (HMAS-5) is higher than that over HA1-MCM-41, which is assigned to HMAS-5 which has stronger acidity than HA1-MCM-41. Furthermore, we observed that the catalytic conversion over HMAS-5 is much higher than that over HZSM-5, which is assigned to that the diffusion of large molecule of 1,3,5-triisopropylbenzene is strongly impeded by narrow channels of HZSM-5 zeolite,