Abstract: In the industry area of process control,datum collection is an important content.The method of OPC for datum colletion not only reduce the workloads but also prove the safety and stabilization of system.In normal times,an OPC server is defined by differential devices,so an OPC server just work for confirmed devices.the price of an OPC server is also a problem for using.It is that reserch an OPC datum access server developed on a third part SDK,and the server provides the following functions:the datum collection from devices,datum simulation,datum writing from client a series of basic functions of an OPC DA server.The server provides service by COM,and it does not provide UI,it runs when a client is avalible.Lots of tags are provided by server,so the server can be used in a huge company.