The system integration industry involves hundreds of enterprises. In this highly competitive environment, new product development becomes crucial to profitability and competitive advantage. New product development involves several activities, each involving different problems. Enterprises use Knowledge Base (KB) to identify effective solutions to the problems occurring at each stage. Producing system integration products involves both design and customization, and therefore each case is unique. Products at different stages of the development process involve different issues. Additionally there is different application from KB. This study takes different degrees of product newness as a focus for examining both new and upgrade products as variable factor, as well as the issues and support involved in new product development. Six cases are used to analyze KB (Knowledge Base) application. The study shows that enterprises should seek different degrees of support from KB and suppliers when facing different technical and nontechnical problems. Regarding technical issues, for really new products it is argument setting of KB application; for upgrade products it is argument setting of KB application. Regarding non-technical issues, for really new products these refer to planned applications of KB; for upgrade products these refer to planned applications of KB.