Dehydration of ethanol to ethylene over modified SAPO and the optimization of reaction conditionswere studied in thiswork. SAPO- 11 and SAPO-34were commercial catalysts.Mn-SAPO-11, Zn-SAPO- 11, Mn-SAPO-34 and Zn-SAPO-34 were synthesized in the laboratory. In NH3-TPD profiles of samples, Mn2+ or Zn2+ modified SAPO-34 exhibited higher desorption temperature of bothweak and strong acid sites and possessed more weak acid sites