Abstract: In many application domains, information is complex and uncertain. Conventional formal concept analysis is unable to express fully the vague and uncertain information. The theory of fuzzy formal concept analysis is therefore introduced, which combines the fuzzy theory proposed by Zadeh with the theory of formal concept analysis. Some conclusions are drawn with a set of objects and a set of attributes proved in fuzzy formal context. Then, the fuzzy concept lattice is formed in fuzzy formal context, which is proved to be a complete one. Some examples are given to illustrate how to form the fuzzy concept lattice.