For a class of linear systems with norm bounded uncertain parameters, the robust H∞ controller and state observer are designed in the case of actuator failures.Considering that the state of the system cannot be measured directly, the state observer is used to obtain state information unknown to the controlled system.Assuming that the actuator of the controlled system is failed, the design of the fault-tolerant controller and the state observer is discussed.According to the definition of robust H∞ controller and Lyapunov stability theory, the matrix inequalities satisfying the robust H∞ controller and state feedback controller are obtained.By using Schur's complement lemma, the matrix inequality is transformed into a standard linear matrix inequality.This linear matrix inequality can be easily solved by the LMI toolbox in Matlab.Finally, the effectiveness of the method is demonstrated by simulation examples.