With the development of computer network technology, network security issues are also making more and more people pay attention. IPsec protocol as a viable solution to IP communications security was put forward, and many IPsec products were also launched. Therefore, to detect and mine possible vulnerabilities of IPsec-related products is important and necessary. Fuzzing test can help us find these vulnerabilities in these IPsec product implementations. In the current popular Fuzzing tools, Peach is a widely recognized open-source fuzzing framework. However, the current Peach is unable to support IKE protocol. The paper achieved fuzzing test for IKE protocol by extending the framework of the Peach.