Abstract: A field survey was conducted on the population dynamics of aphids in potato fields in Hohhot, aimed to provide indispensable foundation for the monitoring and control of the aphids in potato fields. The main aphids in the potato fields in Hohhot were green peach aphid (Myzus persicae) and cotton aphid (Aphis gossypii), and their spatial patterns were of aggregated. The basic components of the aggregated distribution were colonies, and the aggregation intensity decreased with the increase of the population density. By using the optimal segmentation method, the population dynamics could be divided into four periods: (1) colonization period: in earlymiddle June, with the increasing of air temperature and the growth of potato seedlings, alate aphids began to immigrate into potato fields, and the aphids only distributed on seldom plants, with lower quantity but higher aggregation intensity. (2) slowincrease period: from late June to middle July, with the reproduction of aphids, the aphid density had a slow increase, and the aphids diffused gradually with a higher aggregation intensity. (3) quick increase period: from late July to middle August, due to the rapid reproduction of aphids, the aphid density increased sharply, and the aphids distributed over the whole field with a decrease of aggregation intensity, and (4) eclipse period: after late August, with the decreasing of air temperature and the aging and withering of potato plants, many alate aphids emigrated from potato fields, the aphid density declined quickly, and the aphids only distributed on seldom remained living plants with the aggregation intensity somewhat increased again.