Abstract: Though the public interest is protected as one of the important objects under the Anti-unfair Competition Law, there are still a lot of acts of competition against the public interest in the internet. Due to the imperfections of the laws and the uncertainty of public interest, public interest is not duly protected. This article argues that the public interest under the Anti-unfair Competition Law is mainly expresses as fair competition. Based on the judicial practices, this article takes the connotation of public interest as the starting point, then clarifies its history of the protection, distinguishes the interests of competitors, the interests of consumers and the public interest, and then explains what fair competition means, elaborating its main function in justifying which act is fair and promoting fair competition. For the purpose of a more perfect protection of the public interest, the article concludes that an amendment to the Anti-unfair Competition Law and an improvement of judicial practice are necessary.