A mosaic kohlrabi seed-keeping method comprises the steps of (1) sowing: soil working and sowing at the end of August; (2) transplanting: transplanting when the seedling age is 27-30 days, and removing the mutation when planting; (3) management: applying composite fertilizer when the yellow leaves fall off from the live seedling to be transplanted and new leaves grow, and spraying the seedling after transplanting by mixing 20 g imidacloprid with 15kg water; (4) re-planting: at the first ten days of December when dark frost comes, pulling out the mosaic kohlrabi and sunning it for one day; cutting off the leaves when planting on the second day, and transplanting it to the field edge or corner where white radish grows nearby; (5) harvesting: at the early June next year, pulling out the mosaic kohlrabi plant and putting it somewhere shelters from the rain; and threshing after ripening, shell removing, drying and collecting. According to the invention, the mosaic kohlrabi is pulled out for sunning for one day, then planted again, therefore the plant can grow from nutrition growth to reproduction growth; the mosaic kohlrabi is planted being mixed with white radish, therefore the anthesis can be postponed more than half a month, and the mosaic kohlrabi is prevented from mixed pollination with other cruciferous crops and avoiding biological hybrid.