This paper analyzed the existing association rules update algorithm IUA, found out that when the decision makers gave priority attention to the situation of maximum frequent itemsets, this algorithm cannot lower the cost of the database traversal to quickly access to the largest number of frequent itemsets. For the lack of the algorithm, an algorithm which is based on reverse search approach to update association rules is presented. The updating algorithm based on reverse search first generated all frequent itemsets of new itemsets. Then, it spliced the new largest frequent itemsets and original largest frequent itemsets for trimming, get the updated maximal frequent itemsets. This algorithm not only reduces the traversal times in the process of association rules updating, but also realized the priority access to the largest operation of frequent itemsets.