To address the issues of incomplete coverage, limited accuracy, and insufficient timeliness of single data sources in flood inundation analysis, a flood inundation analysis method based on multi-source data fusion is proposed by using the weight of evidence method to fuse heterogeneous data such as flood simulation, remote sensing monitoring, and social investigation. The joint state evidence of “water depth × remote sensing” is adopted to avoid duplicate weighting. The verification results of the example in the Langouwa flood storage and detention area of the Haihe River Basin show that when the submergence probability threshold is 85%, the recall rate of the proposed method in this paper is 8.2% and 5.0% higher than that of single remote sensing monitoring and flood simulation, the F1 score is 4.2% and 2.8% higher, the accuracy is 3.4% and 2.3% higher, and the missed reporting area is reduced by 5% to 8%. Comparing the flood inundation range based on the method proposed in this article with 192 field survey points, all 179 inundation points except for boundary points fall within the inundation area, with a consistency of 100%. Keywords: multi-source data fusion; flood disaster; inundation analysis; weight of evidence method; the Haihe River Basin 〖FL