The invention provides a corrosion detection method for a grounding net, as well as a system. The method comprises the steps as follows: the corrosion potential of detected grounding net metal is measured, constant current step signals are applied to the detected grounding net metal, and the constant current step response signals are collected; the wavelet filter treatment is performed to the collected grounding net soil corrosion electrochemical detection data; and the corrosion electrochemical parameter analysis processing is performed to the grounding net soil corrosion electrochemical detection data after the wavelet filter treatment, thereby generating the grounding net soil corrosion detection result. The grounding net corrosion status is detected accurately and conveniently by the electrochemical detection method.