The Multi-data-type Interval Decision Diagram (MIDD) approach express and deal with the critical marks of attribute incorrectly, while express and deal with the obligations and advices ambiguously, resulting in the inconformity of node expression and the increase of processing complexity. Aiming at these problems, some improvements and expansions were proposed. Firstly, the graph nodes in MIDD with entity attribute as the unit were converted to the nodes with element as the unit, so that the elements of attribute-based access control policy were able to be represented accurately, and the problem of dealing with the critical marks was solved. Secondly, the obligations and advices were employed as elements, and were expressed by nodes. Finally, the combining algorithm of rule and policy was added to the decision nodes, so that the Policy Decision Point (PDP) was able to use it to make decision on access requests. The analysis results show that the spatio-temporal complexity of the proposed approach is similar to that of the original approach. The result of the two approaches' comparative simulation show that when each attribute has only one subsidiary attribute (the most general application situation), the average decision time difference per access request of the two approaches is at 0.01 μs level. It proves the correctness of the complexity analysis, indicating the performances of the two approaches are similar. Simulation on the number of subsidiary attributes showed that, even with 10 subsidiary attributes (very rare in practical applications), the average decision time difference of the two approaches is at the same order of magnitude. The proposed approach not only ensures the correctness, consistency and convenience of the original approach, but also extends its application scope from eXtensible Access Control Markup Language (XACML) policy to general attribute-based access control policies.