One-dimensional flow is often used as a flood simulation. Flood is a type of unsteady flow that can be simulated using HEC-RAS. The result of this model sometimes refers to error due to the unstable analysis program. The stability of the program is affected by the river geometric, the slope of the river bed, and the cross-section characteristic of the river. In the step of flood forecasting, it requires the maximum discharge data and maximum of the water level. The steady flow model is an alternative way to simulate the flood flow. This study aimed to compare the advantages and the disadvantages of steady flow and unsteady flow modeling. Ngotok River, Mojokerto was selected as the case study location. The hydrology modeling was conducted by using the HEC-HMS, and HEC-RAS was equipped for the hydraulic modeling. The result of this study shows that the water level from the steady model is higher than the unsteady model. The time consumption to analyze the unsteady model is longer than the steady model. The average flood water level from the unsteady model is +27.17 m and the steady model is +29.62 m.