The purpose of this study is to analyze the hydraulic characteristics of the ice-harbor fishway by considering its geometrical form and utilize such analysis results as the foundational database to be used when establishing fishways in the future. first of all, the study realizes the same form as an ice-harbor fishway that is currently implemented via a FLOW-3D model and estimated the parameters that were optimal to the numerical mock test. Then, this study analyzed the level of sensitivity of the flow conditions which fluctuated due to the changes in geometrical changes by adjusting the inclination and pocket spacing by using the estimated optimal parameters. As a result, the study arrived at the following conclusions. The vortical velocity increased and had a significant effect on the inclination of the fishway. Furthermore, as the velocity within the vorticity increased due to the narrowed vortical area, it was determined that further studies on vorticities or the determination of the design method for the decrease in vortical velocity were imperative.