The high-quality development of medical security system is a concrete way to achieve common prosperity while guarantee of major diseases is the requirement of the high-quality development of medical insurance. This paper analyzes the construction process of healthcare security mechanism of major diseases and its logical relationship with common prosperity, analyzes the implementation effect and fairness of healthcare security mechanism of major diseases based on the actual situation. Finally, from the aspects of fairness and sustainability, the paper puts forward the direction of institutional improvement that conforms to the requirements of common prosperity.