Abstract: Disclosed is a process for producing light olefins from methanol or dimethyl ether. In the process, the fresh catalyst or the regenerated catalyst is pretreated to deposit a certain amount of coke onto its interior pore surface in advance, to reduce the generation of alkane and heavy olefins, so as to increase the selectivities to ethylene and propylene; and during the production of the light olefins, the pretreated catalyst is used for catalyzing the methanol or the dimethyl ether to produce light olefins. The process can achieve higher yields of ethylene and propylene.