The present invention discloses a method of multi-active detection and a stack member device. Each member device in a stack is configured with a detection interface that is assigned an IP address, wherein the IP address of the detection interface on the designated active device is activated. Each member devices is also configured with an active device election rule, and with a correspondence between the IP address of the detection interface on each member device and the active device election parameter of the member device. Upon detection that the stack has become split, each designated standby device transitions to become an active device and activates the IP address of its detection interface. Each active device then uses the IP address of its detection interface as the source IP address to establish a session with other active devices, finds the active device election parameter according to the source IP address in the received session packet, and elects an active device that maintains its active state according to the configured active device election rule. The present invention implements multi-active detection in a stack.