Abstract: The pure SAPO-11 molecular sieves were synthesized by microwave-assisted method and with pseudo-boehmite and silica gel etc. as raw materials.The method greatly reduced the crystallization time and saved the cost of synthesis.The prepared samples were characterized by powder X-ray diffraction and scanning electron microscopy.The influences of silica source，structure-directing agent，the ratio of silica to alumina and the crystallization conditions（such as time，temperature， and pH） on the synthesis of pure SAPO-11 have been investigated in detail.The results indicated that the influences of pH and crystallization time were significant.The pure phase SAPO-11 molecular sieves were efficiently synthesized via microwave-assisted method using silica gel as silicon source，and di-n-propylamine as template agent under the conditions of crystallization temperature of 185 ℃，crystallization time of 10 h，pH=5.7，and n（SiO2）∶n（Al2O3）=0.6.

Key words: microwave assistance, hydrothermal synthesis, SAPO-11, molecular sieves