Based on the perspective of sustainability， this paper analyzes the current revenue and expenditure of China’s basic medical insurance and its constituent insurance types. Using the revenue and expenditure data of China’s basic medical insurance fund from 2009 to 2022 as the prediction indicator，this study constructs a grey GM（1，1）prediction model to predict the scale and balance of China’s basic medical insurance fund revenue and expenditure. From 2023 to 2030，the scale of China’s basic medical insurance fund will continue to expand，but the growth rate of the fund’s current balance will decline. During the“15th Five-Year Plan”period，the expansion of the medical insurance fund will decelerate，with potential structural risks. Specifically，there is a risk of age structure imbalance in urban employee medical insurance，while urban and rural resident medical insurance encounters government fiscal pressure risks caused by disproportionate welfare tendency and medical service optimization - seeking behavior. Moving forward，we should uphold the safety - net function of the medical insurance system in protecting people’s livelihood，further optimize the operation mechanism of the medical insurance fund，and enhance service quality to ensure the sustainable development of the system.