The invention discloses a ground electromagnetic prospecting method based on an SPSP (Spread Spectrum) coding technology and a detection system thereof. The ground electromagnetic prospecting method based on the SPSP coding technology comprises the following steps of: supplying a current signal hopping according to a certain coded sequence to underground by a sending electrode, and using the current signal as a manual excitation source; receiving an electromagnetic field response message by a receiver, and meanwhile, synchronously recording the sent current signal and the geoelectrical response message of the position where the receiver is located by the receiver; and obtaining ground system response comprising the geoelectrical resistivity through a correlated identification method, and finally obtaining the distribution characteristics of the geoelectrical resistivity. According to the detection system applying the ground electromagnetic prospecting method disclosed by the invention, a sine-wave or square-wave signal in unipolarity or bipolarity in the whole preset frequency range can be sent by a transmitter, a sending sequence can hop according to a preset frequency pattern, and uncorrelated noise can be removed through a correlated identification detection method.