Abstract: An 1-dimension robust PID controller design procedure is developed for the general plant on the basis of modern robust control theory.It has several advantages.First,the parameters of PID controller can be obtained analytically.Second,the controller has only one adjustable parameter which is related to system robustness directly.Finally,the controller can be used for plants with large time-delay.The results are compared with those of conventional techniques which suggests that this method ensures good performance and robustness.