Flood and drought have always been the most frequent disaster in the world record. Cambodia, being at rank of 116 of the most vulnerable country, has suffered so much from flood and drought. That’s why the main purpose of this study is to identify flood and drought characteristic. This study of flood and drought is based on CAESAR-Lisflood, a combination of CAESAR and LISFLOOD-FP. Study area of this case is Pursat Catchment. Calibration and validation are verified using NSE, RSR and Pbais.DEM of the catchment was generated from ArcSWAT and average rainfall was calculated from rain gauge in the catchment. Then, the simulated discharge was calibrated against discharge in Khum Veal station. After discharge was simulated, flow duration curve was created and analysis and inundation maps were generated. Simulated discharge show only acceptable result in calibration. Flow period changes from ending in October or November to around December or even January of the following year. Though, peak discharge increases from less than 632 m3/day to almost 900m3/day, it still occurs round October or November. Flow duration curve shows a low frequency of high magnitude flow (around 500 m3/day) and the possibility of this river never dried out is high, or in other word, low flow (around or less than 10m3/day) in Stung Pursat exists year round. In flood inundation map, the flow doesn’t show a lot of differences but it changes in color which also means it changes in depth. Though, in this study, base scenario is not good enough to create climate change scenario, it also provides the basic understanding of flow in Pursat catchment. Further study should be conducted like the study of flow in water resource infrastructure condition as well as study in climate change scenario.