Abstract: In order to explore the best fertilization method for the breeding of mini-potato of Mincaishu No.4, and provide scientific basis for the high-efficient production of the mini-potato of Mincaishu No.4, the effects of different fertilization methods on the agronomic traits of virus-free seedlings of potato and the yield of mini-potato were explored by taking the virus-free seedlings of the new color potato variety, Mincaishu No.4 as the experimental materials. The results showed that the plant height (64.67 cm, 64.33 cm), and leaf area (237.96, 185.49) of T2 and T1 treatments were the highest, which were significantly different from other treatments. The average tuber number, the average tuber weight per plant and the large and medium tuber rate of T2 treatment were the highest, which were 1.84 grain·plant^-1, 12.42 g·plant^-1 and 39%, respectively. In summary, the best fertilization method for the virus-free seedlings of Mincaishu No.4 was T2 treatment, which was that the organic fertilizer (1.27 kg·m^-2) was used as the base fertilizer, 1/2 MS nutrient solution was sprayed once at 15 d after transplanting, MS nutrient solution was sprayed once at 30 d after transplanting, and 2 MS nutrient solution was sprayed once at 45 d after transplanting. Under this fertilization method, Mincaishu No.4 grew best and the original seed had the highest production efficiency.