For any country, the stage of creating a constitution is a critical historical moment. The success or failure of making a proper and workable constitution has a significant impact on the ebb and flow of a country's political development and the felicity of its people. It is widely acknowledged that the first country with a written constitution was the U. S. A., but in Chinese academic circles, few if any studies have been carried out on the experience of making a state constitution before the framing of the federal constitution in 1787. So the main theme of this essay is a study of the process and impact of constitution making in Massachusetts, along wiht the analysis as popular sovereignty, separation of powers, check and balance, judicial independence, together with the mechanism of turning the theory into practice and institutions. The experience, i.e., the process and result of constitution making in Massachusetts, and its key concept of popular sovereignty, serve not only as a precursor to the American Constitution, but also as a chapter in the history of constitutionalism that any serious study can not afford to skip over.