The invention discloses a real-time comparison method for measuring running errors of broadband electric energy meters. Real-time analysis and comparison are performed on four-path electric energy measurement signals on the secondary side, multiple combination real-time comparison of four-path electric energy measurement signals can be achieved by inputting one path of secondary current and voltage signals to be measured, two paths of electric energy pulse signals to be measured and one path of standard current and voltage signals, real-time harmonic calculation can be further performed on two paths of input analog signals, and accordingly further analysis of electric energy measurement quality is achieved. By means of the real-time comparison method, real-time measurement performance analysis and comparison can be performed on different types of electric energy meters, real-time assessment can be performed on measurement quality of measured analog input signals, a data basis is provided for real-time measurement error analysis for measurement and assessment on different types of electric energy measurement devices, the accuracy and reliability of electric energy measurement of transformer substations are ensured, and the method has good application prospect.