The rough set theory is introduced to deal with vagueness and uncertainty. In some aspects, the rough set theory overlaps with the Dempster-Shafer theory of evidence, but the rough set theory uses partitions to specify rough sets, lower and upper approximations, and then to capture uncertainty in knowledge representation. In this paper, directing against the discrepancy in the specification between the two theories, the authors explore their relationship in order for ones to understand them and open the way of applying them. In addition, in evidence theory, the basic aperation to combine evidences is the orthogonal sum, while in the rough set theory, the basic operation is the intersection of partition. Therefore, “Does the evidence combination correspond to the partition?” is the question which may be naturally raised. An example is presented to show that the answer is “no”.