High reliability and measurement accuracy are the premises and foundations of the practical use of optical transformer in power systems. Based on the theory of power optic sensor and model structure, the implementation plans for magneto-optical glass type as well as all-fiber type current transformer and electro-optic crystal type as well as all-fiber type voltage transformer are classified and compared, the advantages and disadvantages in the aspects of detection algorithms and manufacturing processes are also pointed out. Finally, the problems associated with the practical use of optical sensing technology and research directions are discussed.