Summary: In this paper a possible model is given for handling uncertain information by defining fuzzy knowledge-base as a quadruple of a background-knowledge, a deduction mechanism, a decoding set and some modifying algorithm which connects the background knowledge to the deduction mechanism. We defined two kind of modifying algorithm, and gave evaluation strategies of them. Possibly this evaluation strategy can be improved, or maybe there is a better modifying algorithm. To find these better solutions will be the work of a possible further development.