Abstarct: One of the natural and effective events on human life is the phenomenon of floods, whose prediction has always been investigated. The current research was carried out with the aim of "Flood risk assessment and Vulnerability in Shalmanrud and Langrudrud Khan watersheds in the east of Guilan province". Sentinel-2 satellite images were used for flood zoning in October 2018, October 2019 and November 2021 in the mentioned basins because these types of images are free and have suitable and acceptable quality for flood zoning. With the help of SNAP software, qualitative indexes NDWI and MNDWI were applied to these images to identify flood zones, and by calling flood zoning images in GIS software, the area of extracted zones was calculated by each qualitative index, and the results showed that MNDWI index performed better in identifying flood zones. compared to the NDWI index. In order to verify this issue, the flood was simulated with the help of HEC-RAS software for the return period of 10,25,50,100,200 and 500 years, and the results were consistent with the flood zoning using Sentinel-2 satellite images. In order to prepare flood risk maps, 13 sub-criteria have been prepared: slope, slope direction, curve number (CN),hypsometry, distance from the river, watercourse density, geology, soil, land use, vegetation, bed width and sinuosity. With the help of TOPSIS multi-criteria decision making model, the weight of each criterion was determined and a flood risk map was prepared for each basin. baxsed on the flood risk zoning maps, each basin was divided into 5 areas: very low, low, medium, high and very high in terms of risk and Finally a vulnerability map of the basin was prepared for each return period.