The invention relates to a sunscreen bar capable of isolating ultraviolet A-wave and B-wave simultaneously and a preparation method thereof. The sunscreen bar comprises SOD (superoxide dismutase) oil mixed suspension, titanium dioxide, talcum powder, castor oil glyceride, carnauba wax, candelilla wax, cetyl alcohol, microcrystalline wax, beewax, octyl C12 alcohol and erucic acid oil-based ester. The specific preparation process comprises the following steps of: mixing castor oil glyceride, carnauba wax, candelilla wax, cetyl alcohol, microcrystalline wax, beewax, octyl C12 alcohol and erucic acid oil-based ester uniformly, then adding titanium dioxide and talcum powder, grinding, adding SOD oil mixed suspension, homogenizing and the injecting into a mould, so as to obtain the sunscreen bar. The sunscreen bar is capable of isolating ultraviolet A-wave and B-wave simultaneously, is free of sensitization source, has high safety and high cell viability, furthermore, the sunscreen bar is convenient to use, is portable, and can take supplementing and protective functions in time, so the sunscreen effect is better.