In the nowadays information era, the criminal are making use of modern techniques to commit crime. Traditional police patrol system, hand-written reporting, and oral communication are unable to tackle the new challenges. Since all-day service and overall control are the means to keep our society in good order, information/communication techniques (ICT) are effective supports for police command and control system. Based on the present-day technology, a modern police command and control system should involve two aspects: one is computerization, in which various information systems are deployed, and the other is mobilization, in which mobile techniques are introduced to support police operations. The paper is divided into two parts: in the first part we make a through literature study on command and control systems, and then propose some principles for system design. The system is composed on nine fundamental subsystems: (1) 110 emergency call with automatic number indication (ANI) and automatic location indication (ALI); (2) Computerized command and dispatching system; (3) Geographic Information system (GIS) with global positional system (GPS); (4) Mobile data communication system; (5) Mobile police workstation; (6) Data warehouses; (7) Electronic patrol management system; (8) Crossroad/hot spot monitoring system; (9) Real-time video system. The above system is validated by requirements satisfaction check and evaluated upon technical, economical, and social-ecological feasibility studies. A prototype is implemented as a pilot project for test purpose. After rigorous scrutiny and tests, we come to the conclusion that the proposed system is realistic and applicable. In the near future the system could be supported by the 3rd generation (3G) mobile communication technique and wireless local area networks (WLAN) to become more perfect and powerful to achieve the aim of quick response (QR) in conducting police operations.