With the rapid development of smart substation, digital electric energy meter will eventually replace the traditional electronic energy meter. However, basic error testing method of digital meter is still immature and exhibits low testing efficiency. This paper investigates the advised methods of basic error test proposed by the newly published national standards and enterprise standards of State Grid, i.e., standard digital meter method, standard digital power source method, standard electronic meter method, watt-second method. The relationship between measurement accuracy and calibration real-time of these methods are discussed. Moreover, the corresponding measures of improving the measurement accuracy or shortening the test time are presented to facilitate choosing appropriate calibration methods for digital electric energy meter under different working conditions, which can provide technique reference for the standardized, systemized and specialized development of digital energy meter.