The invention discloses a method for preparing a high-oleic oilseed rape material by utilizing artificially synthesized brassica napus. The method comprises the steps of utilizing the artificially synthesized brassica napus for hybridizing with natural brassica napus, obtaining a great deal of variations through mass exchange and recombination among filial generation chromosomes, and deficiency, insertion, transposition and inactivation of gene sequences, preventing brassica napus oleic acid synthesis from transforming to linoleic acid and linolenic acid, and utilizing mutation accumulation to acquire a high oleic acid material. According to the method provided by the invention, in earlier generation, oleic acid characteristics have no need to be selected, so that the breeding period can be shortened through a generation-adding technique; in earlier generation, a planting group contains about 300 plants (strains), so that compared with thousands of single plants (strains) for mutation breeding, the work load is smaller; during orientation selection, the selective pressure is increased by successive generations, so that the frequency of acquiring different types of high oleic acid is increased, and the breeding efficiency is improved. According to the method provided by the invention, the breeding selection group is small, the work load is small, the variation range is large, and high oleic acid brassica napus genetic resources with the oleic acid content being higher than 80 percent are obtained.