The axiom definitions of entropy, distance measure and similarity measure of fuzzy sets are systematically given and basic relations between these measures are discussed. The concepts of σ- (resp. sub-σ-)entropy, σ- (resp. sub-σ-)distance measure and σ- (resp. sub-σ-)similarity measure are proposed, and some examples of them are listed. The relations between σ- (resp. sub-σ-)entropy, σ- (resp. sub-σ-)distance measure and σ- (resp. sub-σ-)similarity measure are obtained.