Abstract: The information entropy between coarse granularity and fine granularity is comparatively studied，the influence on decision tree caused by coarse granularity and fine granularity is investigated，and the conclusion is provided that the information entropy under coarse granularity is not less than the one under fine granularity.It is shown that the decision tree generated by selecting the expanded attribute under fine granularity is better than the one under coarse granularity.

摘要： 对粗信息粒与细信息粒的信息熵做了比较研究，并研究了粗信息粒和细信息粒对决策树产生的影响，得出以下结论：粗信息粒的信息熵不小于细信息粒的信息熵，细信息粒下选取扩展属性产生的决策树优于粗信息粒下选取扩展属性生成的决策树。