The invention discloses methylionone and a preparation method of a methylionone intermediate. According to an existing preparation method of methylionone, a lot of alkali usually needs to be wasted, and on the other hand, a lot of three wastes are caused. Under the conditions that citral and butanone serve as raw materials, PEG serves as a solvent and metal hydroxide serves as a condensation agent, an Aldol condensation reaction is conducted, and false methylionone is synthesized; the obtained false methylionone is subjected to a cyclization reaction catalyzed by acid, and methylionone is synthesized. According to methylionone and the preparation method of the methylionone intermediate, an adopted PEG-M(OH)x catalysis system improves the synthesis efficiency of the false methylionone, and the ratio of the false methylionone is kept at 68-79%; moreover, an adopted phosphoric acid-normal hexane catalytic cyclization system greatly improves the cyclization yield; an adopted catalytic condensation system can be used indiscriminately for several times, so that the cost is reduced, and environmental pollution is also reduced.