Abstract: This paper aimed to investigate the influence of transplanting density under the conditions of greenhouse on the breeding of minituber from the virus-free tube seedlings of potato, and determine the optimal transplanting density for the virus-free tube seedlings of potato, thus to provide reference for the production. The virus-free tube seedlings of the newly bred potato varieties, namely, Minshu No.2, Minshu No.5 and Mincaishu No.4 were used as the experimental materials, and three kinds of different transplanting densities, namely, 400, 225 and 100 plants per square meter, were designed to study the growth of the virus-free tube seedlings of potato under the three treatments of different transplanting density. The results showed that under the treatments of different transplanting density, the plant height, the number of potatoes per unit area, the number of qualified potatoes and the yield of minituber of the virus-free tube seedlings of the same potato variety all increased with the increase of the transplanting density, while the stem diameter decreased with the increase of the transplanting density. The growth indexes were the best when the transplanting density was 400 plants per square meter, and the tuber number of the qualified minitubers bred from the virus-free tube seedlings of the three potato varieties under the transplanting density was the highest. Under the treatment of the same transplanting density, there were difference among the minituber yield of different potato varieties, among which Minshu No.5 had the highest yield of minituber, with the number of qualified potatoes reaching 493.3 per unit area.