In order to solve the problem that the communication protocol of substation DC power equipment is not uniform, the communication protocol conversion method is used to convert the communication data of different manufacturers' equipment, upload them uniformly, and realize the data display and the customer's application through APP. The remote monitoring system of DC power is composed of acquisition device and APP through protocol conversion, so as to realize the intelligent monitoring of substation DC power supply. The experiment shows that the designed remote monitoring system is able to timely and effectively feedback the information of the DC power supply system in the substation to the APP user. It has very strong generality, and has an important practical value for the safe operation and efficient maintenance of the substation. This work is supported by Natural Science Foundation of Henan Province (No. 162300410173).