The invention belongs to the technical field of chemical synthesis, and particularly relates to a preparation method of optically pure lobeline hydrochloride and an enantiomer of the optically pure lobeline hydrochloride. According to the method, benzoylacetic acid, methylamine hydrochloride and glutaraldehyde are used as raw materials, and a target product can be prepared through condensation, reduction, acylation, resolution, oxidation and hydrolysis reactions in sequence. According to the method, meso-racemic lobeline is derived into raceme through acylation by adopting a desymmetry strategy, so that conditions are created for further resolution, and the use of a chiral catalyst which is high in price and tedious in preparation is avoided. In the splitting step, the product is filtered, the obtained filtrate is subjected to hydrolysis and other treatments to obtain an intermediate compound II, and the intermediate compound II can be recycled, so that the process cost is greatly saved; and moreover, the whole preparation process flow is simple to operate, mild in condition, high in optical purity of the product and very suitable for large-scale industrial production.