Abstract: National health is a fundamental condition of economic and social development, and national medical insurance is an important institutional arrangement to promote national health. The stable operation of medical insurance fund, which functions as the "lifeline" of the medical insurance system, is a premise and foundation of the sustainable development of health care system, which also depends on the level of economic and social development. This paper theoretically analyses the important factors influencing medical insurance fund operation as well as the influence mechanism of the related factors. Then based on dataset of 31 provinces and cities worker medical insurance fund and related indicators, factors affecting the fund income, expenditure and the total balance are explored respectively using panel regression model for empirical analysis. It can be found that there are many factors affecting the medical insurance fund operation and development in the aspects of macro-economic level, micro-economic level, medical resource demand and supply, and urban employee health insurance participation structure. Further, the influencing factors in different regions are different to some extent.

Key words: urban workers, medical insurance fund, accumulated balance, influencing factor