Abstract: the principie of consonance piays an important roie in the traditional theory of harmony,hut for a long timi few experts havegiven special dissertation on it this assay will analyze several stagesin the developmint of the theory of harmony and the basis of theprinciple of consonan ce in counterpoint music.the theory of harmony plays the leading role in the deferent period of the edevelopment of the westem nusic,and the leading role is everincreasing.when it comes to the 21st century,the language of harmony...