Current transformer is the key metering and protection equipment and its performance is directly related to the stable operation of power system. Although traditional oil-immersed current transformer shows excellent electrical performance in the operation，yet it，in case of internal fault，probably leads to explosion accident and poses threat to the safety of person and equipment. Therefore，the research and development of the explosion-proof oil-immersed current transformer is of urgent. In this paper，the principle and key technology of the explosion-proof oil-immersed current transformer are described. The performance of the new type explosion-proof oil-immersed current transformer is verified by test. The results show that compared with the traditional products，the explosion-proof oil-immersed instrument transformer has significantly improved in terms of explosion-proof ability，overload ability and heat resistance performance. The research in this paper can provide valuable experience and theoretical support for the explosion-proof design of power equipment.