Software systems situated in open environment like the Internet are increasingly characterized as socio technical systems that evolve dynamically various variations and changing requirements. To construct such complex software system has become an open issue in the literature of software engineering. This research takes socio technical systems as multiple agent organizations and presents an organization-based program model ORAP that introduces organization metaphors like organization, agent, role and position to construct complex socio technical systems. A series of programming mechanisms like role binding and composition, role-based interaction and self-management of organization were designed to tackle the dynamics issues of socio technical systems by categorizing the organization dynamics at different organization levels. Furthermore, an organization-based programming language called OragentL for implementing social technical systems were proposed, which involves its syntax formal definition at organization, role and composition levels respectively. The OragentL’s compiler and running environment called OragentBurg were introduced and a sample was studied to illustrate our approach and show its effectiveness. 