The purposes of this research are :（1）edit a scale to evaluate the interactions among schoolchildren, and go on to understand the differences among schoolchildren of genders and grades.（2）explore the differences of interaction among schoolchildren of several sorts of family structures and various parents-child interaction.（3）revise “the scale of emotional intelligence for elementary students”, and explore the differences among schoolchildren of various emotional intelligence.Our research targets are 1393 elementary students. We have found that：（1）the development of positive interaction between peers for schoolgirls is better than schoolboys. And the development of negative interaction between peers for schoolboys is more obvious than schoolgirls.（2）the development of positive interaction between peers for the sixth grade is superior to other grades. However, the development of negative interaction between peers for the sixth grade is more obvious than other grades.（3）the development of positive interaction between peers for who live with parents is superior to those living with a single parent; while the development of negative interaction between peers for those who live with a single parent is more obvious than that of those living with their parents.（4）the development  of positive interaction between peers for the type of “frequent-connection-and-mental- cohesiveness” schoolchildren is superior to that of “infrequent-connection -and -mental -incohesiveness” schoolchildren,  while  the  development of negative interaction between peers for the type of “infrequent-connection-and-mental- incohesiveness” schoolchildren is more obvious than to the “frequent-connection -and-mental-cohesiveness” schoolchildren.（5）the development of positive interaction between peers for schoolchildren who score high in emotional intelligence is superior to those who score low in emotional intelligence. However, the development of negative interaction between peers for those who score low in emotional intelligence is more obvious than those who score high in emotional intelligence.