The invention discloses a detector for underground water source detection. The detector comprise a signal input and channel selection circuit, a power-frequency trap wave and input adaption circuit, a low-pass filter circuit, a prepositioned variable gain amplification circuit, a selectable band pass filter group, a postpositioned variable gain amplification circuit, an A/D conversion circuit and a control processing and communication circuit. The detector works under management of setting parameters of a host PC and detects underground water source information obtained by 16 connected probes, the detection data is transmitted to the host PC via a communication interface, and the buried depth and reserve magnitude of an underground water source are analyzed. The detector has the advantages that a new method for underground water source detection is introduced, the detector uses dynamic information of underground water flow to search for the underground water source, and the problem that a traditional water geophysical prospecting apparatus has multiple solutions is solved; and the detector can be widely applied to water supply, water conservancy engineering, mine control water and the like.