In recent years

with the application of multilevel power amplifier in high precision field

the total harmonic distortion （THD）has become an important index in high-precision fields.Firstly

this paper introduces the application of multilevel power amplifier in the field of high precision and the harmonic problems caused by it.At the same time

the root of total harmonic distortion caused in a multilevel power amplifier system is elucidated.Then

the main literature is classified according to the means used to suppress total harmonic distortion

and the advantages and disadvantages of different harmonic suppression methods in topology

modulation strategy and multimodal control are summarized.In addition

the principle and characteristics of the new theory and method of harmonic suppression are emphatically expounded.Finally

a summary of THD suppression methods for multilevel power amplifiers was provided

highlighting research ideas for increasing the number of voltage levels and response speed

etc.