The invention discloses a preparation method for compound stevioside of RA and RD. The method is characterized by comprising the following steps in order: (1) extracting crushed stevia rebaudiana leaves with water and conducting filtration; (2) passing the filtrate through a macroporous resin column, carrying out eluting with an alcoholic solvent, passing the eluent through ion exchange resin, and taking the effluent liquid; (3) adding a decoloring agent into the effluent liquid, conducting filtering and drying, thus obtaining a stevioside crude product; (4) adding an alcoholic solvent for dissolving, performing reflux heating, and during the process, adding the same amount of water as the stevioside crude product so as to make the stevioside crude product dissolved in the system completely; then implementing standing and filtering so as to obtain a crystal; (5) carrying out dissolution with an alcoholic solvent as well as reflux heating again, and adding water for repeated crystallization; (6) conducting washing with an alcoholic solvent and drying, thus obtaining a finished product. The invention has the advantages of: low cost, easy crystallization component control; good mouthfeel of the prepared compound stevioside of RA and RD, no remaining taste, adaptation to market needs; and better product stability.