Abstract: With the development of IoT technology, embedded devices are facing more severe security threats, especially the serious impact of embedded device vulnerabilities on the security development of the IoT industry. However, due to the limitations of hardware resources of embedded devices, dynamic vulnerability detection technologies commonly used in general computer systems such as fuzz testing are difficult to apply directly to embedded devices. Therefore, in recent years, embedded device firmware emulation technology has become a research hotspot in academia. By emulating or replacing the hardware dependency of embedded devices, general and efficient vulnerability detection technologies such as fuzz testing and symbolic execution can be applied to embedded devices. We focus on the latest embedded device emulation technology, collect and summarize top international academic papers in recent years, summarize and classify relevant research results based on the emulation technology and derivative relationships used, and then evaluate and refine these firmware emulators for technical reference for users to choose firmware emulators. Finally, based on the current situation of embedded device firmware emulators, we put forward the challenges and opportunities of firmware emulators and prospects for future research on firmware emulators.