“To large extent, the 1970s marked the end of the Rodgers and Hammerstein revolution”(p.116). For see the Characteristics of Conceptual Musical Plays from "Campany", the birth of the conceptual musical comes from the traditional narrative musical. Inheritance and innovation, its formation is based on the highly mature and perfect narrative mode of the traditional musical play. The interpretation and development of the traditional script musical drama in the 1970s, its creative themes and forms have been perfected and matured, and the inherent routines and models have become accustomed to creators and audiences. At the time when the development of traditional script musicals enters a bottleneck, some creators have actively and boldly reformed and tried the performance form and creative method of musical dramas, so many experimental and breakthrough works have been produced. "Left and Right" is one of the early important works of the conceptual musical drama. Its success and influence are the symbolic works of the conceptual musical drama on the historical stage of musical drama. Since the birth of the concept musical, there have been different opinions on its definition. Its biggest feature is still compared with its traditional narrative musical as Company “was every bit the revolution” (p.120). Different from the musical called Pippin, first of all, the traditional narrative musical plays respect the script first, and there must be a complete plot and summary of the story before the next step of creation. The earliest starting point of the conceptual musical is completely different. It can be a concept, a novel, some interrelated fragments, then use this as the core to create various aspects of creation. Secondly, the traditional narrative musicals are presented in a flat and linear manner in the form of drama. The beginning, development, climax and end are all indispensable. Narrative means to achieve timely emotional venting. The use of space, three-dimensional theater effects, and multi-level narrative techniques are emerging one after another. This is a major breakthrough and unimaginable innovation in the bottleneck period of the development of narrative musicals. The musical "Cat" is different from the popular musical "Phantom of the Opera". “Cat” “was also Lloyd Webber’s first real dance musical” (p.157). "The Phantom of the Theater" is “one of Andrew Lloyd Webber’s greatest commercial success” (p.170), is mainly takes a very clever perspective-that is, taking the pitifulness of selling and the sense of ceremony in the love story to create a variety of strong contrasts-to express the deep and broad obsession, mystic passion , Its protagonist phantom is a person who pursues beauty but is seriously paranoid; this makes me from time to time, because the substitution of the role resonates and looks very excited. Although we can also easily feel that if phantom pursues Christine because he likes music / art, his original purpose cannot be achieved. However, it is this kind of indistinguishability between people and people, it is this kind of passion-driven as long as you like it, you feel that the plot has a shocking power. In comparison, "Cat" can not show some of the impressive plot features of the above-mentioned drama, because its plot is not strong. "Cats" is a slightly childlike story. A group of cats chose an immortal cat at an annual party. From the plot point of view, why was the immortal cat finally selected, and there is no reason for the plot.