Abstract: To meet the needs of magnetic precision seeding, a magnetic powder coating made of talcum powder and iron powder was suggested. By the magnetic powder coating, cabbage seed and kohlrabi seed were magnetic granulate coated and magnetic treated. The experiment investigated that the combined influence, under the condition of external magnetic field, of different iron powder content in magnetic powder on the germination rate, the germination potential and the vital index of the cabbage seed and the kohlrabi seed. The experimentation indicated that coating with magnetic powder had inhibition for seed early germination, but if the iron powder was controlled in 30%, under the combined action of the magnetic field, the germinating rate and vital index were advanced, and the young seedling diathesis improved, meanwhile, the growth of seedling roots was promoted. Basing on the germinating rate, the germinating potential, the vital index and the young seedling diathesis from the experimentation, we can ensure that the optimum quantity of iron powder in magnetic powder for coating: cabbage seed was 20%, kohlrabi seed was 10%, both the intensity of magnetization magnetic field were 100 mT. The results provide a scientific basis for the promotion of the magnetic precise seeding technology.