For single-phase intelligentwatt hour meters which have reached the designed service life and choise severaltypical environments,usethe on-site calibrator, on-site verification device, precision and stable power supplier and other equipments to measure on-site error detection, on-site daily time detection, on-site power comparison and other tests on the in used single-phase smart energy meter. Then, the single-phase intelligent watt hour metersarebe taken back to the laboratory and tested by the electric watt hour meter verification device under the reference condition. Compare the two kinds of test data with the test data before the single-phase intelligent watt hour metersare connected to the network to analyze the attenuation of various functions of the single-phase intelligent watt hour meter after reaching the design life, and evaluate the single-phase intelligent watt hour meter"s continued life extension reliability.