Based on the analysis of the traditional storage pattern of electronic medical records (EMR) data, the paper proposes another storage plan with fine-grained structure of XML mode according to the HL7 CDA.This storage plan can not only reduce the medical records data storage space and the query time effectively, but also facilitate the clinicians and researchers to use medical records data for medical information statistics, clinical auxiliary diagnosis and other areas, so as to expand the application spaces of the EMR.