Recently, internet violence occurs frequently. Generally, netizens' initial aim is to punish the evil and encourage good deeds,but their behavior and words hurt the privacy rights of citizens.Besides,it affects the interests of the state and society.On the hand, the law provides citizens the right speech.At the same time,laws also requires citizens to take corresponding obligations. This paper analyzes the concept of freedom of speech, expands the source of law and presents the characteristics of Network supervision. Then, the paper makes it clear the relationship between Network supervision and the freedom of speech. Finally, the paper clarifies the legal rules of Network supervision.