Current overload may happen during the actual operation of the smart electric meters. Once this happened, some meters may calculate a reduced power or even a reversed power, and when the current returns to the normal metering range, the meters may still behave abnormally.In this paper, based on the field operation failure case of smart electric meters, the paper simulates the overflow effect of ADC model and filter in the measurement chip, explains the above two phenomena in principle, and gives the solution, and verifies the correctness of the solution through experimental data。Put forward corresponding guidance to the provincial electric power company under the overload condition.