National Health Insurance (NHI) will be implemented on March 1, 1995. The estimate annual number of claim items reviewed under NHI will amount to at least 930 million for outpatient and 26 million for inpatient respectively. The only way to process those data efffiently is to set up standards for reivew, and to identify abnormal cases for manual review throughout the computer analysis. finally, the objectives of NHI claim review system are quality assurance, process simplification, shortened reimbursement time by the design of simplification & the management of outliners. With respect to the case payment which will be adopted in inpatient reimbursement, 28 minimum requirements which are written in English & Chinese, based on diagnosis, have been completed. These minimum requirements were spelled out by the related departments of Chang Gung Memorial Hospital and reviewed by different associations of specialties in an effort to establish a peer review model under PPS or under DRGs in the future. These 28 cases are highly recommended to be implemented under Case Payment, and more minimum requirements should be completed by the cooperation of medical centers and specialty associations. In addition, the average variation of severity of illness in different levels of hospitals must be taken into consideration when setting up the reimbursement for case payment in order to pursue a fair & reasonable payment system. Finally, the related models of peer review and computerization process are also presented here.