The invention discloses an operation error monitoring device for an electric energy meter in a meter box. The monitoring device is installed on the bus side in a branch meter box and comprises a front data acquisition unit, a metering chip calculation unit, a main control core calculation unit, a local data communication unit and a data transmission unit, and the front data acquisition unit acquires original data on the bus side of the branch meter box, and calculates bus-side real-time energy consumption data by using the metering chip calculation unit, the metering chip calculation unit communicates with the data of the electric energy meter in the meter box through the local data communication unit, acquires the frozen electric energy data of the electric energy meter in the meter box, and calculates the operation error of the electric energy meter, and locally transmits the calculation result or uploads to a remote server through the data transmission unit. According to the invention, high-timeliness on-line monitoring of the metering error of the electric energy meter in the metering box is realized by utilizing the existing data metering system architecture and additionally arranging the operation error monitoring equipment in the branch metering box.