Flooding in Ho Chi Minh (HCM) City is caused by heavy rain, high tide, flood discharge from upstream, urbanization-land subsidence and climate change. Simulation programs used for flood control of downstream of the Dong Nai river system basin, including model of rainfall flow (NAM) and hydraulic model (MIKE 11). Simulation scenarios include tidal flooding in consideration of urbanization-land subsidence and climate change in the area. The urbanization data by the year of 2030 is used in accordance with urban space development planning. The impacts of the urbanization-land subsidence, climate change and implementation of the Irrigation Plan 1547 by the year of 2030 is considered according to the scenario of 2030RCP4.5 as the baseline for comparison and the scenario of 2030RCP4.5_P1547. Predicted results show that water levels in the main river as well as in the urban area have increased significantly, resulting in increased flooded areas.