Abstract: The purposes of this study are: (1) To reveal general low and characteristics of children's cognitive development for friendship qualities; (2) to search children's cognitive structure of friendship qualities.The subjects were 100 children aged 6,8,10, and adolescents aged 12 and 15 who were from a kindergarten, a primary school and a high school in Beijing.The results showed: (1) The children's cognitive structure for friendship qualities consisted of five dimensions which are personal communication and conflict resolution,exempting and competition,liking and appreciating each other,common activities and helping each other,intimate personal intercourse; (2) for children and adolescents aged 6—15 years old the importance of the five dimensions are different,the sequence of their importance are: common activities and helping eacho ther,personal communication and conflict resolution,exempting and competition,liking and appreciating each other,intimate personal intercourse; (3) there are substantial developmental differences in different dimensions of friendship qualities.The common activities and playing are developed at age 6 as well as at other ages.It seems that the critical age of its development must be at earlier ages than 6 years.However,other dimensions locate lower level at 6 years old and gradually growth from middle childhood to early adolescence,the critical period is from 10 to 15 years old. (4) Sex differences were found only in dimension of common activities at children aged 12 years old along with boys higher than girls, in dimension of conflict resolution along girls get higher scores than boys,and in dimension of appreciating each other at adolescents aged 15 years old,along with boys higher than girls.

Key words: Friendship Qualities, Cognitive Development of Friendship Qualities, Structure of Friendship Qualities, Method of Story Explaining