To resolve the irrationality in the definition and measurement of intuitionistic fuzzy entropy, a new axiomatic definition for intuitionistic fuzzy entropy was proposed, and a new measuring formula was structured. Firstly, the existing differences in research of axiomatic definition for intuitionistic fuzzy entropy were analyzed, its defects and insufficiency were also pointed out. Secondly, an improved axiomatic definition for intuitionistic fuzzy entropy and a calculation formula of intuitionistic fuzzy entropy were proposed. Finally, the new formula was compared with the existing formulas for intuitionistic fuzzy entropy by examples. The results of the example analysis show that, the proposed entropy formula can reflect better the uncertainty and fuzziness of intuitionistic fuzzy sets, and the capability to discriminate the uncertainty of intuitionistic fuzzy sets is stronger.