This study investigated the relationships between social network sites use (SNS use)and social network sites addition (SNS addition), and the mediating effect of positive self-presentation as well as the moderating effect of relational-interdependent self-construal(RISC). Based on cluster sampling, 658 college students who have used SNS for more than three months were recruited to participate in this study. The results indicated that: ( 1 ) SNS use significantly positively predicted SNS addiction; (2) positive self-presentation playe...