Abstract: The development of behavior and social relationship of two infant golden monkeys in two breeding cages respectively were recorded 22 months continually with instantaneous sampling method. The results show: (1) They weaned at 19 -20 months of age; (2) Aunt behaviors, which include snatching, protecting and caring, are conspicuous among group females; (3) The relationship between father and infant is affiliated and tolerant; (4) Before weaning, infants were the subjects which all the group members protected, then, after they began to enter into the social relationship net of the group, they gradually were sli- ghtly blamed blt the group members. In addition, the occurrence of some social behavior patterns was noticed.

Key words: Rhinopithecus roxellanae, infant, social relationship, individual development, case study