Abstract:In the era of multi-source heterogeneous big data, big data presents new features such as cross, diversity and variability. The applications of big data in a wider range of fields have new requirements for data fusion. Under this background, the connotation of data fusion is enriched and expanded. The generalized data fusion includes the fusion of data resources, the fusion of model methods, and the fusion of decision-makers' knowledge and experience. This study analyzes the characteristics of multi-source heterogeneous data fusion at three different fusion levels: data level, information level and decision level, and discusses challenges for data fusion in storage, application and analysis technology, data management as well as value determination. What's more, corresponding suggestions are putted forward, which benefit for enterprises, government and other entities to effectively manage data resources and provide reference for more in-depth data fusion analysis.