Abstract: Data fusion technology is the fusion of redundant or complementary information from multiple types of homogeneous or heterogeneous sensors to accurately assess the situation of the observed object, and make correct judgement about things. With the development of medical technology, medical data in different modes are increasing rapidly. Compared with single mode, using data fusion technology to process multi - mode medical data can obtain more abundant and comprehensive information, avoid information silos, and provide strong information support for medical research. In this thesis, we briefly introduced the concept and principle of data fusion technology, summarized the working principle, advantage and disadvantage of different levels and commonly used algorithms in data fusion technology, and finally introduced the application of data fusion technology in the field of disease prevention, diagnosis, treatment and rehabilitation.