Embodiments of the invention disclose a locating terminal, method and system used for sealed space locating. The terminal comprises an active reader and a locating apparatus, wherein the active reader is used for sending a radio-frequency signal with a preset frequency, receiving a response signal fed back by a to-be-tested device configured with a responder according to the radio-frequency signal and sending the response signal to the locating apparatus; and the locating apparatus is used for obtaining position information of the terminal and obtaining position information of the to-be-tested device according to the signal intensity of the response signal and the position information of the terminal. According to the locating terminal, method and system, the radio-frequency signal is sent into the device in a sealed space based on active RFID, the response signal returned by the device is received, and calculation is performed according to the signal intensity of the response signal and the position information of the terminal to obtain the position information of the device; and the locating terminal, method and system has the advantages of high locating speed and high locating precision.