This paper focuses on the attitude control of flexible spacecraft with time-varying input delay.A composite hierarchical control structure,which combines delay-dependent H_∞ control with disturbance-observer-based control (DOBC),is designed to achieve stable control of both attitude angle and attitude angular velocity.Advantages of the proposed method include:1) the disturbance caused by vibration is compensated accurately to reduce the influence of disturbance on control effects;2) a delay-dependent state controller is designed to reduce the effects of delay on attitude;3) the decomposition coefficient of delay integral inequality is introduced in the process of function solving,which may reduce design conservatism.Finally,numerical simulations are used to verify the effectiveness of the proposed method and to show the effects on close loop system performance by time delay bound and decomposition coefficient.