Abstract: In this paper the formula of requisite linear damping for overcoming shimmy is derived according to the point contact theory of wheel shimmy.However damp-ing property of the hydraulic shimmy damper is mostly non-linear. Two methods have been presented in this paper to treat this case. They are tangent method and minimum equivalent linear damping method.Their relation has been found, too. It has been demonstrated by computation that the methods are both effective and reliable.