This paper aims to use the method of evidential reasoning （ER） algorithm based on fuzzy uncertainty to provide the basis for missile quality condition assessment， especially to deal with many unquantifiable factors， as well as factors which are inaccurate， unclear and incomplete. The ER algorithm operates in a system where both unknown and fuzzy data are modeled under the unified framework of distributed fuzzy belief structure to form a fuzzy belief decision matrix. Using the grade matching method， the numerical data and various forms of qualitative （fuzzy） evaluation information are finally transformed into fuzzy belief structure. This method can fuse the evaluation levels of important parameters without iteration on the premise of maintaining the independence with fast degradation speed， so as to improve the sensitivity and applicability of the evaluation process.