High-frequency dynamic monitoring of flood disaster using remote sensing technology is crucial for accurate decision-making of disaster prevention and relief. However, the current trade-off between spatial and temporal resolution of remote sensing sensors limits their application in high-frequency dynamic monitoring of flood disaster. To deal with this challenge, in this study, first, to construct the cloud-free MODIS data cube, we removed the cloudy areas in MODIS original data cube by using the information provided by GPM rainfall data. Then, we fused the cloud-free MODIS data cube and Landsat-8 data by using the spatio-temporal data fusion algorithm to construct the high spatio-temporal resolution (Landsat-like) data cube. Last, the high spatio-temporal resolution (Landsat-like) data cube was used for high-frequency dynamic monitoring of flood disaster. Our study had three main results: (1) The differences between cloud-free MODIS data cube and observations were small and the cloud-free MODIS data cube could be used for subsequent studies. (2) High spatio-temporal resolution (Landsatlike) data cube reflected the spatio-temporal changes of flood well and could be used for the highfrequency dynamic monitoring of flood disaster. (3) There were two floods occurred in the study area from July 17, 2021 to October 16, 2021. The first flood occurred from July 17, 2021 to September 15, 2021, with maximum affected area of 668.36 km 2 . The second flood occurred from September 18, 2021 to October 16, 2021, with maximum affected area of 303.88 km 2 . Our study provides a general method for high-frequency monitoring of flood disaster.