A fall detection method, device, and system are disclosed in this application for detecting whether a target object falls in a detection area. The fall detection method includes: receiving a WIFI signal transmitted by a transmitter in the detection area and extracting CSI data from the WIFI signal； preprocessing the CSI data to obtain CSI data to be identified, and processing the CSI data to be identified through a deep neural network to determine whether the target object falls in the detection area. In this application, a deep neural network is adopted to perform fall detection and the detection accuracy is improved.
