A detecting method for detecting a dynamic status in a space, wherein at least two wireless communication devices are deployed in the space and capable of performing a channel state detection to obtain a channel state information, the detecting method comprising: controlling the at least two wireless communication devices to perform the channel state detection in a registration stage to obtain a plurality of registration-stage channel state information; determining an environmental data of the space according to the plurality of registration-stage channel state information; controlling the at least two wireless communication devices to perform the channel state detection in a detection stage to obtain a plurality of detection-stage channel state information; and determining an intrusion situation of the space according to the environmental data and the plurality of detection-stage channel state information.