Provided are a detection method and device for link keep-alive between an Access Controller (AC) and an Access Point (AP). The method includes: setting a maximum permissible heartbeat keep-alive failure number; and performing link keep-alive detection between the AC and the AP based on the maximum permissible heartbeat keep-alive failure number by virtue of a heartbeat message or message retransmission. By the solution, a maximum permissible heartbeat keep-alive failure number is set, and a maximum retransmission interval is set for link keep-alive detection between the AC and the AP based on the maximum permissible heartbeat keep-alive failure number and a heartbeat keep-alive period, so that the problem that the AP frequently gets offline and frequently re-accesses the AC due to link quality reduction to seriously impact user experiences can be effectively solved.