Through the systematic analysis of the current research results on the effectiveness of traditional Chinese medicine（TCM） in the prevention and treatment of diabetes and its promotion dilemma， it is believed that cohort study， as an observational research method， is particularly suitable for evaluating complex and individualized interventions such as traditional Chinese medicine in the prevention and treatment of diabetes. Considering the design features and relevant practices of prospective cohort studies， it is specifically proposed to carry out prospective cohort studies using a modern TCM diagnostic and treatment system for diabetes， centered on "state-targeted differentiation and treatment"， and framed by "classification-staging-syndrome differentiation". Focused on personalized prevention and treatment， long-term multidimensional assessment of therapeutic effectiveness and syndrome changes， this paper gives in-depth exploration of the advantages and value of applying prospective cohort studies in the effectiveness evaluation of TCM in prevention and treatment of diabetes， aiming to provide insights for clinical researches on TCM for diabetes.

To summarise the clinical experience of Professor TONG Xiaolin in treating prediabetes combined with overweight or obesity using the method of relieving depression and reducing turbidity. It is believed that prediabetes belongs to the category of "spleen-heat syndrome" in traditional Chinese medicine， and its core pathogenesis is center fullness with internal heat， while obesity is the initiating factor for exacerbating center fullness and internal heat， therefore， it is of great significance to reduce the risk of diabetes by interrupting the transformation between overweight， obesity and glucose metabolism abnormality. It is proposed that the main pathogenesis of prediabetes combined with overweight or obesity is qi depression and turbidity obstruction in middle jiao， with qi depression as the root and turbidity obstruction as the cause， forming a treatment idea with the method of relieving depression and reducing turbidity as the core. In clinic， Dahuang Huanglian Xiexin Decoction （大黄黄连泻心汤） is used as the basic prescription， with a primary focus on directing the turbid downward， supplemented by regulating qi， which embodies the concept of "promoting movement through descent， then figuring out the root of spleen-heat syndrome. Furthermore， the treatment is flexibly modified based on the patient's deficiency-excess syndrome to ensure individualized therapy.