Rhodium chloride is prepared from rhodium metal powder by: adding rhodium powder and hydrochloric acid into U-shaped electrolytic tank, providing AC current onto two electrodes to dissolve in solution and obtaining aqueous solution of rhodium hydrochloride, filtering the solution of rhodium hydrochloride, distilling to obtain concentrated liquid, and crystallizing in a crystallizer to obtain aquacompound of rhodium chloride or anhydrous rhodium chloride, which can be used in fine chemistry.