The New Cooperative Medical Scheme (NCMS) was implemented in 2003 in response to the poor state of health care in rural China. It holds the primary objective of insuring rural residents against catastrophic health expenses, protecting them from impoverishment caused by medical expenses. The objective of this study, therefore, is to explore variation in the determinants of household enrolment in this scheme and the impact of enrolment on health care utilization and medical expenditures in three large geographic regions in China and further to simulate the reimbursement package design in order to achieve better financing protection and policy effectiveness.