Abstract: Some diversity appraisal models of opportunity set are based on distribution of alternatives in the set. Different with views that diversity of opportunity set is determined only by rang size of the distribution, the article presented diversity of opportunity set is determined by range size and uniform condition of the distribution. The maximum distance between the alternatives represented the range of the distribution. The Gini coefficient of the distance series represented the uniform condition of the distribution. Two appraisal rules of diversity of opportunity set are presented based on the maximum distance and the Gini coefficient