This paper puts forward an alert method for underwater mobile target based on moored vertical array，and discusses its theories of time-frequency transient characteristics detection and spatial correlation detection. The underwater mobile vehicle is monitored by utilizing the time-frequency and spatial difference between ocean environment and target noise，and this method has high detection probability with simple calculations. The vertical arrays are hanged on mooring cables of moored submerged buoy or directly used as mooring cables，and they can be used for long period and wide range fix-point real-rime monitor for underwater mobile target，because of its good tactical performance and adaptation to wide-range water depth.
