To give the specific hydrofoil for tidal turbine, the design optimization method for hydrofoil was investigated. The proposed approach was based on genetic algorithm. The function of lift coefficient, lift-drag ratio, drag coefficient and pressure coefficient were chosen as the objective functions. XFOIL software was employed to evaluate the hydrodynamic efficiency and pressure on the surface. Several typical design objective functions were established under different design requirements, and the corresponding hydrofoil curves were given in the proposed method. Numerical result shows that this approach can deal with the hydrofoil design optimization problem for tidal turbine according to the specific design requirement. The given hydrofoil can not only improve hydrodynamic coefficient but also avoid its cavitation problem. The location of maximum thickness is closer to trailing edge for minimized pressure coefficient, while it approaches the leading edge under maximized lift coefficient condition. The hydrodynamic efficiency and pressure distribution for various attack angles should be considered to achieve the designated objective function.