The occurrence of parametric rolling will threaten the ship safety. The bilge keel is selected as the device of stabilization and suppression of the parametric rolling for an ONR tumblehome ship. The influence of the installation angle and breadth of the bilge keel on the roll damping is calculated based on the viscous CFD method. A new retractable bilge keel stabilizer is designed to improve the stabilization effect. The rolling characteristics of the ONR tumblehome ship in regular head seas with different bilge keel schemes are analyzed by using the three-dimensional potential flow method. The simulation results show that the bilge keel can effectively suppressthe parametric rolling and stabilize the ONR tumblehome ship.In particular, the designed retractable bilge keel can obviously suppressthe parametric rolling.