A method for improving the light olefin yield in the process of preparation of a light olefin using an oxygen-containing compound, more specifically, in which, a multi-stage dense phase fluidized bed comprising k secondary pre-carbon deposition zones (k≧1) and n secondary reaction zones (n≧1) is used as a reactor, and a multi-stage dense phase fluidized bed regenerator comprising in secondary regeneration zones (m≧2) is used as a main equipment, and by re-refining hydrocarbons with four or more carbons obtained in the separation section, or adding naphtha, gasoline, condensate oil, light diesel oil, hydrogenation tail oil or kerosene in the reaction zone, the method primarily solves the problems in the prior art of the uniformity of carbon deposition amount and the carbon content of the catalyst being difficult to control, and the light olefin yield being low.