If there are lots of redundancies in the policies loaded on the policy decision point (PDP) in the authorization access control model, the system will occupy more resources in operation and consumes plenty of evaluation time and storage space. In order to detect and eliminate policy redundancies and then improve evaluation performance of the PDP, a redundancy related to combining algorithms detecting and eliminating engine is proposed in this paper. This engine cannot only detect and eliminate the redundancy related to combining algorithms, but also evaluate access requests. A Resource Brick Wall is constructed by the engine according to the resource attribute of a policy's target attributes. By the Resource Brick Wall and the policy/rule combining algorithms, three theorems for detecting redundancies related to combining algorithms are proposed. A comparison of the evaluation performance of the redundancy related to combining algorithms detecting and eliminating engine with that of Sun PDP is made. Experimental results show that the evaluation performance of the PDP can be prominently improved by eliminating the redundancy related to combining algorithms.