The main issue in designing CSCW system is how to provide efficient collaboration mechanisms. This paper originally introduces the concept of CSCW into the design of a modern police command center system. Then we discuss the design and implementation of a cooperative supporting platform for the police command center system. During the design process，we propose a hierarchical cooperative mechanism based on task and discuss several concrete cooperative methods. Finally we propose an implementation prototype GZ-PCCS based on the hierarchical cooperative mechanism and a “Centralized-Distributed” hybrid architecture.