Abstract: Privacy has always been a social institution. It not only helps individuals maintain their dignity and resist social pressure, but also promotes social construction and unity. Privacy may take various forms like custom, contract and right. In traditional society, privacy is mainly based on custom. While in modern society, privacy right has become a more important form. The reasons for this change are as follows: the advancement of information technology has broken the border between different social classes; the improvement of social material conditions has allowed people to enjoy more independent private space and to form diversified social life scenes; with the reorganization of spatial structure and public-private relationship, social intimacy between individuals has become much weaker than before. Traditional privacy customs can no longer meet new social needs. Meanwhile, the form of right is more suitable for privacy’s modern trends like fragmentation and personalization. But as long as individuals still need intimate relationship and social intercourse, they have to share privacy among people, organizations or society. Therefore, in modern society, privacy right cannot be the only form of privacy institution, and privacy customs still have opportunity to be reborn.