The 14th Five-Year Plan for National Health explicitly proposes elevating the comprehensive prevention and control strategy for chronic diseases to a national strategy, aiming to address the growing demand for long-term management and individualized treatment of chronic diseases. In this context, the adaptive treatment strategy (ATS), as an innovative treatment model, offers new ideas and methods for the management and treatment of chronic diseases through its flexible, personalized, and scientific characteristics. To construct ATS, the sequential multiple assignment randomized trial (SMART) has emerged as a research method for multi-stage randomized controlled trials. The SMART design has been widely used in international clinical research, but there is a lack of systematic reports and studies in China. This paper first introduces the basic principles of ATS and SMART design, and then focuses on two key elements of the SMART design: re-randomization and intermediate outcomes. Based on these two elements, four major types of SMART designs are summarized, including: (1) SMART designs in which the intermediate outcome corresponds to a single re-randomization scheme (the classical type), (2) SMART designs in which no intermediate outcome is embedded, (3) SMART designs in which the intermediate outcome corresponds to a different re-randomization scheme, and (4) SMART designs in which the intermediate outcome and the previous interventions jointly determine the re-randomization. These different types of SMART designs are suited for solving different types of scientific problems. Using specific examples, this paper also analyzes the conditions under which SMART designs are applicable in clinical trials and predicts that the mainstream analysis methods for SMART designs in the future will combine frequentist statistics and Bayesian statistics. It is expected that the introduction and analysis in this paper will provide valuable references for researchers and promote the widespread application and innovative development of SMART design in the field of chronic disease prevention, control, and treatment strategies in China.