The current measurement method in the power industry today mainly relies on current sensors. With the development and progress of modern technology, the power system is facing unprecedented challenges. Traditional current sensing technology is difficult to adapt to the pace of the times, and the new generation of current sensing technology is constantly evolving. More and more attention by all walks of life and has been widely used. Tunnel magneto resistance current sensor has the characteristics of high linearity, high sensitivity, low cost, simple structure, etc., so it has become a very potential sensor product. Taking the current sensor developed by tunnel reluctance technology as the core, this paper introduces the working principle of tunnel reluctance current sensor, the advantages and disadvantages of various structures and their application fields, and the improvement methods of different defects. Furthermore, it summarizes the research status and future prospects of sensor array.