Based on measurement error of mine power supply, power supply centre of Shendong Group was taken as example, combined with the actual production, the analysis of the error was conducted from equipment, environment, staff, the power supply form, the reasonable selection, update and check of metering mechanism, improvement of equipment were put forward. The analysis and practice showed that the key of reducing error is to control and reduce the net cost equipment and improve staff management, reasonable metering equipment and operation could reduce the net cost and metering error and improve the power management.