This paper presents theoretical and experimental studies of H∞ control for a flexible plate. Firstly, by a particular integral transformation to the time-delay equation, the standard state equation without explicit time delay is obtained. Then, a H∞ time-delay controller is designed based on the standard state equation using the linear matrix inequality. Finally, simulation and experiment are carried out to demonstrate the validity of the proposed controller. Simulation and experimental results indicate that, the time-delay controller presented in this paper is available for small time delay and large time delay a well. Furthermore, this delay controller is robust to the variance of intrinsic parameters of the plate and time delay.