This paper introduces the design of a smart operation maintenance box based on mobile network. It is a hand-held device for power data acquisition and analysis. It can be considered as a bridge between the on-site operation and maintenance operation. It realizes the data and resource sharing between the on-site side and data center side. On one hand, it is able to regulate on-site operation, data collection, and upload the experimental data in real-time. On the other hand, the on-site team is able to call for the resources located in the data center side anytime for technical support. Using the proposed smart box can improve the professional and intelligent level of the on-site operation, boost the efficiency of the operation and maintenance and ability of equipment status control, and enhance the capability of status maintenance and auxiliary decision making, which is significant for the construction of smart grids. This work is supported by Science and Technology Project of State Grid Corporation of China (No. 524625160034).