Debussy is the avant-garde of 20th century music. Not only did he combine music with colors, but also the bridge between Eastern and Western music, fusing Eastern musical elements into his works. Debussy's piano works consist mainly of Klavierstücke, and the Preludes Book I is the culmination of his musical skills. This essay therefore focuses on Debussy's Preludes Book I. Chapter One discusses Debussy's music styles; Chapter Two gives an introduction of his creative techniques in the preludes; Chapter Three analyzes Debussy's styles of music and designs of phrases; Chapter Four provides my approach for interpretation, especially on tempo rubato and pedals. Chapter Five summarizes my analysis and points out a direction for future research.