Class cohesion could be used to evaluate the design quality of classes, to develop test measures for object-oriented software and to restructure poorly designed classes. Among a number of class cohesion measures proposed in the last decade, H. S. Chae?s measure is based on the structure of the reference graph of a class, which overcomes the limitations of most class cohesion measures. However, it only considers the patterns of interactions among the members of a class partly and hence does not satisfy monotonicity, which might cause the measuring results inconsistent with intuition in some cases. This paper first analyzes the limitations of typical cohesion measures for classes in detail, and then proposes an improved cohesion measure ICBMC. Finally, this paper exemplifies the advantages and applications of ICBMC.