Compared with turn-by-turn beam diagnostic techniques widely used in electron storage ring, bunch-by-bunch diagnostic technology allows the measurement and analysis of each bunch, offering a more comprehensive understanding of the internal state of the electron beam with results that are closer to the true physical model. Recent advancements in data acquisition equipment and signal processing algorithms have laid the foundation for the continuous development of bunch-by-bunch diagnostic techniques. This article provides an overview of the basic principles and architecture of bunch-by-bunch diagnostics, summarizes exploratory work and research achievements in this field by major domestic and international research groups, highlights the research approach, latest findings, and technological applications explored by the Shanghai Synchrotron Radiation Facility (SSRF) team. The future research directions worth attention and development trends are discussed, offering valuable insights for researchers dedicated to the field of beam measurements.