🔖 The flood caused by dam failures always lead to a great great amount of property damage and even loss of human and wild life. While multi-objective dam can provide a lot of benefit, its failure or improper operation may lead to unexpected loss.Hence the main aim of the paper is to develop mathematical models for simulating dam break hydraulics using the HEC-RAS software to simulate the dam break flood in complex real river floodplain. The simulated model has been used to predict and analyze the flood due to the failure of dam.