Medical insurance in USA for international students is different from what you have in China and will be different from what American students have. Usually American students at the secondary schools have their health insurance under their family plan and international students should plan to buy insurance independently. Colleges and Universities offer more comprehensive health insurance plan to international students since they do have contract with big insurance company, however, the secondary schools in many cases do not offer this type of plan. Each individual student then should do research and find an appropriate on with good coverage. Price and coverage vary depending on plans.
