The emergence of ubiquitous computing environment will change the service architecture of business information systems such as Decision Support System (DSS). This paper aims to describe how the decision-making capability and context-aware computing are jointly used to establish ubiquitous applications. To do so, an amended DSS paradigm: CKDDM (Context-Knowledge-Dialogue-Data-Model) is proposed in this paper. Under the CKDDM paradigm, a framework of ubiquitous decision support systems (ubiDSS) is addressed with the description of the subsystems within. To show the feasibility of ubiDSS, a prototype, CAMA-myOpt (Context-Aware Multi Agent System - My Optimization), has been developed.