If patents have been included in a technical standard and thus have become standard essential patents (SEPs), the SEP holders normally have to commit to the Standard Setting Organization (SSO) to license their SEPs on fair, reasonable and non-discriminatory (FRAND) terms. Although the FRAND commitments already put constraints on the patentees, more and more disputes over FRAND licensing fees involving SEPs are reaching antitrust enforcement agencies and courts, perhaps due to the fact that the FRAND commitments are often not workable. As demonstrated in the case Huawei v. IDC in Chinese courts, SEPs have special characteristics compared to non-SEPs, i.e. the licensing of SEPs relates more to the public interest, the holders of the SEPs may be thought to have dominant positions in the licensing market of their SEPs, the holder of the SEPs often have made commitments to license on the FRAND terms, and the holder of the SEPs should be allowed to use the injunctive relief only in limited circumstances. This article also proposes that Article 55 of the Chinese Antimonopoly Law (AML) should be reconsidered because it exempts the undertakings who exercise their IPRs in accordance with the laws and administrative regulations on IPRs from the application of the AML. However, as this article shows, the excessive royalty requested or the injunction sought by the holder of SEPs may not violate the patent law, but nonetheless may violate the antitrust law.