This paper reviews the new challenges, new trends and key technologies of multi-source and heterogeneous information fusion in multi-domain integrated operations. First, this paper analyzes the challenges of multi-source and heterogeneous information fusion in multi-domain integrated operations from the aspects of architecture, information difference, processing process and adaptive parameters. Secondly, in view of the above challenges, the paper summarizes the development trend of multi-source information fusion, multi-source intelligence and integration. Finally, four key technologies of multi-source and heterogeneous information fusion are summarized based on the above development trends.