In conceptual model of Knowledge-Based System (KBS), there is an antagonistic contradiction of reusability-availability.Researching knowledge interaction in it is a critical method to resolve the contradiction. However, the previous researches have devoted limited endeavor to the problem. This paper starts by reusable UPML architecture, and applies the techniques in distributed software engineering to study the non-manual interactions among reusable knowledge components. The adapter in UPML is first split into two independent parts by operational functions, an architecture for KBS which focuses on the interactions among the components is proposed. Then, Matching Agent Group is taken as the interaction medium between task knowledge and Problem-Solving Method (PSM), and a method to localize the PSM which undertake task is designed. Finally, CORBA bus is regarded as the interaction medium between domain knowledge and PSM, and a means to integrate distributed knowledge source and coordinate PSM is presented. The result of analysis shows that the approach provided in this paper can bridge two abstract levels, namely the reuse of knowledge components and KBS architecture. Thus the availability of KBS will be improved while using this approach. Keywords Knowledge-Based System; Conceptual Method; availability; knowledge reuse; knowledge interaction; distributed computing . INTRODUCTION Since Chandrasekaran presented the concept of knowledge sharing and reuse [1], developing KBS has been a crucial issue in the field of knowledge engineering [2]. It is an elementary research to exploit knowledge sharing and reuse on Internet (e.g., Semantic Web, Knowledge Grid, Semantic Grid, etc.) [3]. To attain the reusability of KBS in most great extent, various knowledge engineers adopted Conceptual Method (CM) to model it. Some classical conceptual models include KADS [4], CommonKADS [5], KARL [6]. In those, CommonKADS is most extensive in influence to subsequent models, which defines several types of conceptual knowledge using axioms, including Task Ontology, PSM and Domain Ontology, i.e. knowledge component. Several projects, including KCSRDP, HPKB and RKF, were based on it [7]. Although the researches impressed on the orthotropic development and reuse of the knowledge components, they pay little attention to the interaction among them. Thus, with the reusability of system strengthened, its availability is degraded. On the contrary, Fensel first investigated the knowledge interaction in KBS, and proposed a kind of classical software architecture of KBS based on Adapter, called UPML (The Unified Problem-solving Method development Language) [8], [9]. This work mainly focused on the interaction relationships among knowledge components in reusable architecture level. But it was unconcerned about the specific behavior in the interactions. Thus high availability of system has not been obtained yet. Protégé [10] and the IBROW project [11] are two mature researches based on the UPML architecture. But they deviated from the original intentio...