With the deep reform of China's medical system, especially the advancement of the tiered diagnosis and treatment system, the role of general practitioners in the primary healthcare system has become increasingly significant. General practitioners are not only the first line of defense for residents' health, but also key executors of disease prevention, diagnosis, treatment, and health education. This article analyzes the classification of "major, minor, acute, chronic" diseases and the "4 virtues" positioning of general practitioners (namely adept at treating minor illnesses, identifying major illnesses, referring acute illnesses, and managing chronic illnesses), exploring the crucial functions and challenges of general practitioners in the era of new medical reform. The article points out that although the tiered diagnosis and treatment system aims to optimize the allocation of medical resources, it still faces challenges such as the ambiguity of the classification of "major, minor, acute, chronic" diseases and the uneven distribution of primary healthcare resources. General practitioners play a vital role in this system, needing comprehensive clinical diagnostic and treatment capabilities, and to establish clinical judgment standards and treatment protocols in collaboration with specialists. To address these challenges and fully leverage the role of general practitioners in the modern medical system, urgent reforms and optimizations in general medical education and practice are needed, along with strengthening the role of general practitioners, to ensure the improvement of medical service quality and efficiency while achieving a fair and sustainable health security system.