This thesis is the supplementary document of the new music theatre composition “Pi”，which is divided into two parts. The first part is the textual explanation of the creative idea, material and paragraph design, and the second part is the original music score containing "Pi".

Pi is a new music theatre work for pipa with voice and live electronics，and is inspired from Reincarnation of Tibetan Buddhism, which is similar to a circle phenomenon. Every point of the cycle is the beginning as same as the end. In other words, there is no beginning and no end in a circle. According to the circle as the basic concept, this composition uses infinite non-cyclic decimal circumference Pi (3.1415926...) as the pitch materials, which form a "ten-tone series" for the melodic and rhythm organization in all parts of this composition. At the same time, a Pi's Chinese homophonic poem is quoted as compositional structure and musical drama: shan/mountain/3,dian/top/.,yi/one/1,si/temple/4,yi/one/1,hu/kettle/5, jiu/Wine/9,er/two/2,liu/willow/6,wu/dance/5,shan/fan/3,wu/dance/5…… This Chinese poem expresses wavering people in the temptation of the secular world and the positive struggle against negative power, as well as the abandonment of merits, fame and wealth, leaving the personal evaluation to the world in the end.

The thesis is divided into four chapters: the first chapter is the preface; the second chapter presents the background and ideas of this composition and introduces some related repertoires；the third chapter is the explanation and analysis of music structure, stage design and live electronics; the last chapter is the conclusion of thesis.