Network impacts on the copyright system, the legal system of copyright under the network environment is trampled, and network copyright infringement has become a very common phenomenon. In this case, other social norms not only deviate from laws, but also conlfict to, which creates serious consequences. Social norms against copyright seriously threaten the copyright system, and even affect the belief in the rule of law among publics. The reason of the formation of network social norms against copyright is that the copyright boundary is overexpansion, copyright system cannot make agreement with other social norms. Therefore, it is necessary to reform the copyright system under the network environment, modify system of fair use and legal permission, deifne the boundary of copyright, protect the cultural right of publics, make consistent of the copyright system and other social norms, and eventually eliminate the network social norms against copyright.