In his works,Debussy often applies technical devices including various types of scales,short yet diverse musical materials,chordal parallel motion,and weakened cadential progression,which seems different from the principles of structural organization in the common practice period and causes confusion in analyzing the structural organization of his works.This article draws on the concept of the intervallic alternation of tritone and perfect fifth as the principles of structural organization,and on this basis,combines the pedal tones and the voice- leading by step motion throughout as the analytical perspective of the inner-structural support of the music.Then, by analyzing the material construction,voice-leading,and structural organization of Debussy's three instrumental works,the applicability of this analytical perspective and its flexibility in practical application are demonstrated.