The term "business system" refers to the methods which use to manage their information or knowledge. All companies employ business systems during the development of new software, mechanical equipment or other projects. There are several stages in development projects. There are stages of planning, development, system examination, and upgrade. However, because business knowledge and system development knowledge are united in the systems engineer individual, and the final system image is designed in the engineer’s mind, the knowledge earned in the project is not adapted to the next system development project. Business knowledge and system development knowledge are different. A unification of measures for value of these two types of information is needed to treat the information equally. Then, this paper aims to achieve the decision support agent. This decision support agent should have the function of evaluating the value of knowledge and supporting judgment through all stages of the project. Additionally, because the environment around the system development is always changing, a function to evaluate the importance of knowledge from the data stream is needed so that the decision support agent may acquire and interpreted information in real time.