Abstract: The main products of methanol to olefins are ethylene and propylene. Therefore it is important of study the influence of reaction conditions on product distribution for improving the yield. Based on the 60wt/a industrial MTO device, this paper research the effect of temperature, pressure, carbon content, catalyst reserve and circulation rate on the product distribution. Results show that increasing the reaction temperature can significantly increase the selectivity of dienes and methane. When the temperature is above 490℃, the acetylene content increases obviously, which is harmful to the subsequent separation process. Low pressure is beneficial to increase ethylene selectivity. Higher carbon content can improve the selectivity of ethylene and propylene and reduce the yield of C4 and C5+. The catalyst reserves and circulation affect the residence time distribution of catalyst, and larger cycle is favorable for producing more ethylene.