The invention discloses a method and a system for detecting an AP by a user process. The system kernel obtains the AP information from the received beacon message information, preprocesses the acquired AP information, constructs the socket message according to the AP information, and sends the socket message to the user process. The user process, through extracting the AP information from the socket message, updates the storage unit, and the storage unit selects the hash chain list according to priority. The system enables the user process to search and compare the storage units with AP information, and the kernel no longer maintains the storage unit, thus the stability, maintainability and performance of the system are enhanced.