This paper considered the influence of uncertainty in designing a variable structure flexible spacecraft attitude stability controller，and it provided one robust variable structure controller.The model can guarantee that the system has asymptotic stability under a certain condition,can reach the sliding mode hyperplanes in a limited time under a certain condition,and has good performance in sliding mode hyperplanes to the system. The controller is good according to the numerical simulation results when assuming the system inertia to be 5% uncertainty, still keep good performance and has good robust stabilities.The controller can be further improved when adopting a border lager,because it can effectively solve the shiver problem,and at the same time keeps the performance basically intact.