This paper extends the logic of Knowledge, Belief and Certainty from one agent to multi-agent systems, and gives a good combination between logic of knowledge, belief, certainty in multi-agent systems and actions that have concurrent and dynamic properties. Based on it, we present a concurrent dynamic logic of knowledge, belief and certainty for MAS, which is called CDKBC logic. Furthermore, a
model is given for interpreting this logic. We construct a
proof system for the logic and show the proof system is sound and complete, and prove the validity problem for the system is EXPTIME-complete.