The theories, principles, and methods of think tank science and engineering are all derived from practical experience. For a long time, specialized think tanks and think tank research at home and abroad have exhibited many common characteristics and laws in the development and application of various theories and methods, and yielded products that have delivered significant policy impacts and socio-economic benefits. In summarizing the understanding of such laws, the knowledge system, disciplinary connotations, and methods and principles of think tank science and engineering are tested. Based on in-depth analysis of representative think tank research at home and abroad, this chapter looks into the embedded theories and methods of think tank science and engineering as an empirical reference for future think tank practice. It verifies, at the same time, the reasonableness of the framework and the understanding of the laws governing think tank science and engineering.