In this paper, an Adaptive and Active Computing Paradigm (AACP) for personalized information service in heterogeneous environment is proposed to provide user-centered, push-based high quality information service timely in a proper way, the motivation of which is generalized as R4 Service: the Right information at the Right time in the Right way to the Right person, upon which formalized algorithms of adaptive user profile management, incremental information retrieval, information filtering, and active delivery mechanism are discussed in details. The AACP paradigm serves users in a push-based, event-driven, interest-related, adaptive and active information service mode, which is useful and promising for long-term user to gain fresh information instead of polling from kinds of information sources. Performance evaluations based on the AACP retrieval system that we have fully implemented manifest the proposed schema is effective, stable, feasible for adaptive and active information service in distributed heterogeneous environment.