This paper summarizes the policy evolution, the present situation of supplementary medical insurance for employees in China, analyzes the existing problems. The conclusion is that China's supplementary medical insurance for employees is quite different, fragmented in terms of liable entity, financing source, sustainability, treatment design, claim management, fund administration. It is urgent to standardize, unify supplementary medical insurance for employees, so as to improve the accuracy, security level of the supplementary layer in the multi-level healthcare security system, to alleviate the economic burden of patients with high medical expenses