This report studied the individual number, their favorite habitat, and change pattern of family and group number in Cheolwon Basin, starting in the early Oct. 2004 until late March. 2005 to investigate the ecological features of the Red-crowned Crane and the White-naped Crane. The Cranes arrived Cheolwon Basin in mid-October until next mid-March, and passed the winter in mid-November until next late-February The most visiting number amounted to 550 individuals and, that period was the most frosting mid-January to mid-February. The White-naped Crane visited Cheolwon Basin in autumn, the early winter and spring. Approximately, the wintering-number is 550 individuals, also, the mid-March was the peak-period of arrival and, the number amounted to 2,162 individuals. The cranes chose the farming area around mountains as their wintering habitat and were less likely to choose the farming area around lake as habitat. The Red-crowned Crane and the White-naped Crane showed the different periodical pattern in familial and group numbers. In case of the crane, the familial pattern was stable, but varied in grouping number, and this pattern was similar to the variation of overall individual number. And, also, the most grouping number was shown in the most freezing period of wintering period. The White-naped Crane showed the similar pattern of the Red-crowned Crane that is, stable family number and varying group number, this pattern affected the total number of entire individuals. Grouping number increased in migration period. Parasite infection rate is G japonensis 35.0%, G vipio 38.7%.