The medical information system has been applied in hospitals widely, which makes hospitals acquire notable management benefit and economic benefit. When hospitals enjoy the quick service decision and convenient management because of informationization, they are also in the danger of data loss. Data disaster recovery is the guarantee of the hospital informationization construction, and the base to ensure the normal medical service of hospital. In the article, the data disaster recovery mode in the medical information system is studied and the design principles of hospital data disaster recovery system are systematically analyzed.