The invention discloses a technology for synthesizing methanol dimethyl ether through biomass gasification. The technology comprises the steps that gasified gas is prepared from a biomass material through a fluidized bed gasifier, hydrogasification, reforming, oxygen/steam gasification, reforming and mixing after reforming are carried out, and methanol dimethyl ether is prepared from hot mixed gas obtained after methanol is generated. The biomass gasified gas can be added to any procedure of an existing methanol production device of a methanol plant, and mixed with coal-based synthesized gas in the methanol plant to be synthesized into methanol together, existing air separation, purification, CO transformation, decarburization and methanol synthesizing devices in the methanol plant can be fully utilized, and investment cost can be greatly reduced. Methanol or methanol dimethyl ether prepared in a biomass multiple gasification mode has the advantages of being high in quality, simple in technology and high in utilization rate, reducing cost and the like.