A method for positioning a wireless terminal, and a related device and system are provided. The method includes: obtaining, by a wireless terminal, a positioning service period and an identifier of a positioning channel from a first access point; switching, by the wireless terminal, to the positioning channel in the positioning service period; and broadcasting, by the wireless terminal, a location measurement message through the positioning channel, so that at least three access points in an access point group where the first access point is located obtain positioning measurement data after receiving the location measurement message, so as to estimate a location of the wireless terminal. Embodiments of the present invention can shorten positioning time of the wireless terminal, reduce power consumption, and improve utilization of a network wireless channel.