In this study, we successfully fabricated dense and thin 13X molecular sieve membranes without any cracks, pinholes or other defects on porous α-Al2O3 tube by combination of 3-aminopropyl triethoxy silane (APTES) surface modification, vacuum pre-coating sol technology and hydrothermal crystallization method. The effects of APTES concentration and hydrothermal crystallization number on 13X molecular sieve layers were studied emphatically. The results demonstrated that the best 13X molecular sieve membranes with a thickness of about 10～15 μm could be obtained with 46 mg/ml of APTES surface treatment and 2 times of hydrothermal crystallization. The purification results indicated that the above 13X molecular sieve membranes could deeply purify the trace amount of dimethyl ether, methanol and propanal impurities to below 1?10-6 mol/mol from gaseous olefins at the initial concentration of 20?10-6 mol/mol under room temperature, exhibiting much more excellent purification performance than that of granular 13X molecular sieve adsorbents. In particular, the breakthrough times of 13X molecular sieve membranes for dimethyl ether, methanol and propanal were 16 h, 44.7 h, 94 h in N2 system, and 25.2 h, 102 h, 178 h in C2H4 system.