The outbreak of COVID-19 was the most serious public health crisis in nearly a century，with devastating effects on global public health，society and the economy. Based on the fully understand the significance of strengthening the safety net of national public health，this paper summarizes the development of China’s public health system and its contribution to the national health improvement，and deeply analyses the main problems existing in our national public health system，including the lagging development of the public health system，unclear function orientation of the disease prevention and control institutions，imperfection of the epidemic monitoring and early warning and emergency response capabilities，lacking integration of the public health system and the medical service system，and the imperfection of the incentive and restraint mechanism within the public health system. And then problem oriented，this paper puts forward six overall goals for knitting up national public health system，involving the establishment and improvement of the “national basic public health system”，the implementation of “health into all policies”，the definition of the function of public health institutions at all levels，the improvement of the coverage and level of public health services，the improvement of the capacity of community-level health services and the strengthening of the guarantee mechanism for the construction of public health system，as well as five main tasks at hand，containing the reforming and improving the disease prevention and control system，strengthening the capacity for monitoring，early warning and emergency response，improving the system for treating major epidemics，improving public health laws and regulations，and giving full play to the supporting role of science and technology in preventing and controlling major epidemics，in order to lay the foundation for building a healthy China and effectively safeguard national health.