Based on the US Healthcare Information and Management Systems Society (HIMSS) Electronic Medical Records（EMR）adopting model, the paper analyzes the concept of EMR at home and abroad,and gives detailed system constitution of HIMSS EMR, including Controlled Medical Vocabulary (CMV), Clinical Data Resposiry (CDR), Clinical Decision Support System (CDSS),Computer Aided Order Entry(COPE), Clinical Document Architecture (CDA), etc.