Abstract: The auto control technology, fault diagnosis technology and communication technology are all integrated to research and develop the oil production and water injection distributed control system (DCS) on offshore drilling platform, which controls the parameters such as the ratio of water injection, oil production, flow rate and liquid level and so on. The expert system and selftuning PID/PI control strategy are adopted to get high stability and rapid response. The DCS communicates with Ethernet and data high way(DH) plus network and makes use of the Rsview 32 configure software building up the computer monitoring system, which has the online debug function, automanual switching without disturbance function and self diagnostic function. The DCS includes two sub systems that are offshore platform oil production system and water injection system. The MSG function of PLC can make the data communication between the sub systems, which has the ability to debug the system without stopping any sub system and thus can update the system easily. The chief computer and the manager computer can make common decision to change the parameters, which make the system safer when the system encounters difficulty. The system has human machine interface and it improves the oil field automation level and it is safe and reliable

Key words: offshore drilling platform, oilfield development, oil production, water injection, reliability