The invention relates to the technical field of medicine, and particularly relates to a intermediate for preparing obeticholic acid, a preparation method of the intermediate and a preparation of obeticholic acid. A route is provided to take acetaldehyde as electrophilic reagent, compared with a method of introducing ethenyl and ethyl iodide through an aldol condensation reaction, the yield is sharply improved; cyclohexylamine salt is refined to form a compound (V), the product quality can be sharply improved; double bonds are hydrogenated and then carbonyl is reduced so that ethenyl can be reduced, and by controlling appropriate temperature, by-products of deethylation can be sharply reduced. The method is mild, green and environmentally friendly, besides, the yield is higher than an existing preparation method, the route reaction condition is economical and effective, and suitable for industrial production on a large scale.