Abstract: The author has designed a specialized ruler for analyzing misconnected energy meters in the electric energy measurement. This article focuses on the wiring judgment ruler for misconnection analysis and introduces a general usage method for using such a ruler. This method has a universal and unique analysis process, and easy to master. This method is suitable for both indoor teaching and on-site analysis of misconnected energy meters. At the same time, this article also proposes a method for directly writing the reactive power expression using the active power expression in misconnection analysis, which has a positive effect on improving the efficiency of misconnection analysis.