DNA / RNA - protein interactions are critical to all organisms, especially in the regulation of DNA replication, transcription and repair, and RNA transport and translation. At present, a variety of in vivo and in vitro methods have been developed to analyze DNA / RNA - protein interactions, such as affinity purification schemes, EMSA and chromatin purification methods, but they cannot perform single-molecule real-time imaging analysis and effectively analyze the mechanism of DNA / RNA - protein interaction. The combination of fluorescence probe and microscope provides an effective tool for researchers to study its interaction mechanism.