In this paper, the authors presented a robust PID controller design for time delay system. Utilizing the gain-phase margin tester method, a specification-oriented parameter region in the parameter plane that characterizes all admissible controller coefficients sets can be obtained. The PID controller gains are then directly selected from the parameter region. And the designed controller can guarantee the system at least a pre-specified safety margin to compensate for instability induced by time delay. A compromise between the performances of the system with the above mentioned and smith predictor is also included.