The electronic warfare is a key force of the information war, whose capabilities can be enhanced based on microwave photonics (MWP) technology due to the broadband, high speed, parallelism, and compactness. Microwave photonics technology, as applied to electronic warfare systems, involves the signal generation, transmission, and processing. Firstly, the mission and capability requirements of electronic warfare were presented, and the core elements affecting the effectiveness of electronic warfare was analyzed. Secondly, the advantages of MWP applied to the electronic warfare were discussed in detail. Taking the optical beam forming as an example, MWP technology overcomes the beam-squinting effect. Finally, towards the transition from electronic warfare to electromagnetic spectrum warfare, the challenges and development trend of MWP were proposed.