Current transformer plays an extremely important role in AC measurement, relay protection, maintenance control of power equipment and other related fields of electric system. At present, electromagnetic current transformer has exposed many shortcomings gradually, such as poor insulation and weak anti-interference ability. while electronic current mutual inductance is expected to become the main equipment for detecting current in the future due to its good insulation, small size and digitalization. By describing the research and development status of electronic current transformers, this paper focuses on Rogowski coil current transformers (Rogowski coil current transformers), low-power current transformers (LPCT) and optical current transformers, by analyzing their respective structures and working principles, this paper summarized their advantages and disadvantages, and put forward some improvements. On this basis, it pointed out the challenges faced by electronic current transformers in equipment power supply, environmental adaptation, sensing methods, etc., and looked forward to its future trend from the sensing mechanism and sensing materials.