The time division multiplier（TDM）is an important part of the analog electronic energy meter and also the all-important source of measuring errors.This paper performs quantitative research and analysis on measuring errors with TDM under harmonic conditions.According to the working principle of TDM，the theoretical expression for measuring errors under harmonic conditions is deduced.The correctness of the proposed theoretical expressions is validated through simulation calculations.The TDM energy meter is comprehensively compared with the digital electronic energy meter in terms of the measuring accuracy and cost.Finally，the measuring rationality of electric energy in the harmonic background is discussed.This paper provides a theoretical basis for the quantitative analysis of the error of the measuring system and can be used as a reference for designing electronic energy meters applicable to measurement under harmonic conditions.