Abstract: Accurately sensing the operational status of power transmission and transformation equipment and promptly implementing effective maintenance strategies are crucial for ensuring the safe and efficient operation of the new power grid. With the advantages of good insulation, anti-electromagnetic interference, distributed measurement, high measurement accuracy, and so on, optical fiber/optical sensing is developing rapidly in the field of power transmission equipment measurement. This paper introduces the optical fiber/optical sensing principle and main research progress, including basic electrical quantity (voltage and current), equipment state quantity (temperature, humidity, pressure, and vibration), insulation state quantity (decomposition product and partial discharge). Moreover, the advantages and disadvantages of different monitoring methods are comparatively discussed. On this basis, this paper focuses on the analysis of the difficult problems and development trends that have not been overcome by the existing technology, hoping to provide a reference for the improvement of the holographic perception ability of the new power system.