In order to improve the reliability of the system, and to effectively inhibit the surge in the hot swap process, the hot plug protection circuit based on LTC4364-2 is designed. In this paper, we analyze the demand of multi module structure in the large scale system, and then introduce the design process of the hot swap protection circuit. The verification results show that the designed circuit can not only effectively inhibit the surge current in the hot plug, but also can effectively avoid the damage of the 60 V/DC continuous high voltage to the load. The protection circuit has been put into use in the actual safety control system, and the use of the system is verified by the system.