A system and a method for detecting multi-level intrusion events are provided. The system includes an area recognition module and an area classification module. The area recognition module performs a geometric topology operation to recognize a plurality of areas in a ground plane that has a plurality of boundaries and a plurality of gates, and each of the areas is constituted of at least one of the boundaries and at least one of the gates. The area classification module defines a plurality of security levels and classifies each of the areas recognized by the area recognition module as one of the security levels. Accordingly, the system is able to automatically recognize the areas in the ground plane, set the security levels of the areas, and generate the corresponding detection areas and tripwires according to the security levels of the areas.