In this paper, we propose a PolGALS language for safety critical GALS(Globally Asynchronous Locally Synchronous) systems. The formal syntax and semantics are given and its compilation and implementation are defined. The language is based on timed CSP (communicating sequential process) style rendezvous between clock domains, aiming at modelling the timed behavioral of safety critical GALS systems. PolGALS is used to design timed behavioral pattern to implement timing requirements, e.g. delay, timeout, deadline, timed interrupt, etc. PolGALS provides a mechanism for implementation of timed behav...