The invention discloses a security strategy conflict detecting and eliminating method based on a Hicuts algorithm. The conflict detecting method comprises the steps of: classifying rules of a security strategy by using a classification mode of the Hicuts algorithm to generate a classification decision tree regarding the rules; and performing conflict detection on the rules of the same leaf node of the classification decision tree to obtain a conflict detection result. The eliminating method comprises the step of modifying the rules having conflicts in the conflict detection results to eliminate the conflicts. The method for detecting and eliminating conflicts among the rules of the network security strategy has the complexity o(n), and greatly improves the conflict detecting and eliminating efficiency.