The main goal of this paper is to identify what will affect a child s decision of choosing someone as a good friend, and further, to identify why some children have been chosen as others best friends more than once, which means popularity. We draw on a dataset with 11889 observations by conducting a series of standard tests in 2017 spanning 4 provinces in China. We use cognitive (standard math score) and non-cognitive performance (esteem, depression, and grit) and appearance (HAZ and whether the student is overweight) as our key explanatory variables, and we standardized these key variables to identify which factor contributes to the decision of choosing friends and which contributes more while choosing friends. Our first finding shows that math score, depression and whether the student is overweight significantly contribute to the decision of choosing friends. The children who do better in math, have lower tendency to depression and not overweight will have 4.9%, 2.2% and 2.4% higher possibility to be chosen as friends than their counterparts, respectively. Furthermore, when considering popularity of children, we find the similar results. The two main findings show that one may become more popular if he has higher cognitive ability and good appearance. Acknowledgement : We gratefully acknowledge the financial support by National Science Foundation of China (Grants: 71603261); The Ministry of education of Humanities and Social Science project (Grants: 16YJC880107).