Refers to the medical expenses of employees who participate in the basic medical insurance exceed the maximum payment limit of the overall fund 1 degree, and then enter the large medical insurance. Large medical expenses subsidy insurance is a supplementary medical insurance established by the government for the basic medical insurance organization of urban workers, aiming at subsidizing the part of the insured whose medical expenses exceed the cap line. Units and employees in the basic medical insurance at the same time, each insured person and unit should pay a large amount of medical subsidies to the social insurance agencies to pay the insured person's medical expenses over the top line. Law Based on Article 2 of the Social Insurance Law of People's Republic of China (PRC), the state establishes social insurance systems such as basic old-age insurance, basic medical insurance, industrial injury insurance, unemployment insurance and maternity insurance to protect citizens' right to receive material assistance from the state and society in accordance with the law in case of old age, illness, industrial injury, unemployment and maternity.