As a standard of communication and storage for medical digital images, DICOM has been playing a very important role in integration of hospital information. In DICOM, tags are expressed by numbers, and only standard data elements can be shared by looking up Data Dictionary while private tags can not. As such, a DICOM file's readability and extensibility is limited. In addition, reading DICOM files needs special software. In our research, we introduced XML into DICOM, defining an XML-based DICOM special transfer format, XML-DCM, a DICOM storage format, X-DCM, as well as developing a program package to realize format interchange among DICOM, XML-DCM, and X-DCM. XML-DCM is based on the DICOM structure while replacing numeric tags with accessible XML character string tags. The merits are as following: a) every character string tag of XML-DCM has explicit meaning, so users can understand standard data elements and those private data elements easily without looking up the Data Dictionary. In this way, the readability and data sharing of DICOM files are greatly improved; b) According to requirements, users can set new character string tags with explicit meaning to their own system to extend the capacity of data elements; c) User can read the medical image and associated information conveniently through IE, ultimately enlarging the scope of data sharing. The application of storage format X-DCM will reduce data redundancy and save storage memory. The result of practical application shows that XML-DCM does favor integration and share of medical image data among different systems or devices.