Abstract: Microwave frequency measurement is an important part of electronic reconnaissance. With the development of radar electronic warfare, the operating frequency of microwave increases rapidly. Conventional electronic frequency measurement schemes cannot meet the development of electronic reconnaissance due to their limitation in measurement bandwidth. Approaches of microwave frequency measurement based on photonics have the characteristics of large instantaneous bandwidth, low loss and immunity to electro-magnetic interference. According to the current frequency measurement schemes of microwave signal based on photonics, five technical approaches are introduced and discussed, including instantaneous frequency measurement, photonic-assisted microwave channelization, multi-frequency measurement, microwave frequency measurement based on photonic analog-to-digital conversion, photonic compressive sensing. Moreover, the potential of integrated optics for photonics-based microwave frequency measurement is briefly discussed. In the development of microwave frequency measurement, the photonics-based method has a broad prospect of application.