In recent years，medical big data industry has developed vigorously in China，benefiting from the opportunity rendered by the combination of policies on health care medical big data，“Internet + medical health” and smart hospitals. This paper teases out the development background of medical big data and comprehensively presents the scale，characteristics，service model and business logic of the medical big data service market. It further analyzes service providers，application scenarios，technology and business strategies and cases and envisions the future development trend from the perspective of policy，application demand and model innovation.