Field experiments were conducted to study the effect of density control method on the potato tuber size distribution. The planting density of 60 000, 90 000 and 120 000 holes/hm² with 1 or 3 stems per hole were conducted with the variety of Youjin in 2014, and the planting density of 60 000, 80 000 and 100 000 holes/hm² with 1 or 2 stems per hole were conducted with the variety of Kexin 13 in 2015 respectively. The yield of tubers of the grade 30–150 g increased by increasing the planting density or increasing stems, while the yield of tubers of the grade over 150 g decreased. To early maturing variety of Youjin, the planting density of 120 000 holes/hm² with 3 stems per hole and harvest at 60 d after emergence was suitable for seed potatoes production, while 60 000 holes/hm² with 3 stems per hole suitable for marketable tuber production. To late-maturing variety of Kexin 13, the planting density of 80 000 holes/hm² with 2 stems per hole and harvest at 80 d was suitable for seed potatoes production and 60 000 holds/hm² with 2 stems per hole suitable for marketable tuber production.