Cross-cultural adaptation is a splendid accomplishment in the realm of contemporary Chinese music theatre. Up to 1999, there have been 11 Shakespeare's plays adapted into 16 theatric genres. In early 2000's, "Shake-Xiqu", cross-cultural adaptation of operatic Shakespeare in Chinese, had blooming development. There are three kinds of adaptation in Chinese opera based on Shakespeare's plays: 1) Adaptation in a Chinese style. 2) Adaptation in an occidental style. 3) To perform the Shakespearean play in English but in the form of Chinese opera. In terms of the former two, the adaptation always involves the difficulties of cultural transfer, cross-reference of the texts, character design, language translation and the conventionalization of performance. In particular, Shakespeare was so good at the arrangement of complex structure, double cross, irony, word play, equivoque and blank verse that would increase the difficulty of adaptation into Chinese opera. The conventionalization of performance, including script, modeling, acting, language, music and dance, is the element of Chinese opera. Therefore, the adaptation of Shakespeare's plays will inevitably concern the conventionalization of performance, so as to present the refinement, symbolism, imagination and visualization of Chinese opera on the stage. Wu-Tou, literally means "thecrucial components", is the key point of composition for the Chinese opera. This article outlines the following crucial components to adapt Shakespeare's plays into Chinese opera : 1) cultural transfer; 2) the characteristics of theatric genre; 3) modification of the original story; 4) the focus of language; 5) the constraint on conventionalization of performance. This writer tries to balance the characteristics between Shakespearean plays and the Chinese opera for adaptation by these crucial components, and to provide a useful approach to cross-cultural adaptation.