A three-electrode array local electrochemical information testing system and a testing method, the testing system comprising: a concentric ring three-electrode array, a high-speed switch and an electrochemical workstation, which are electrically connected in sequence; the concentric ring three-electrode array comprises a plurality of concentric ring three-electrode units, adjacent concentric ring three-electrode units being separated by an insulating material; a concentric ring three-electrode unit comprises a ring-shaped auxiliary electrode, a solid-state reference electrode and a wire-shaped working electrode; the ring-shaped auxiliary electrode and the solid-state reference electrode are both formed in an ring-shaped shape; the wire-shaped working electrode is located within the solid-state reference electrode, the wire-shaped working electrode being separated from the solid-state reference electrode by means of the insulating material; the solid-state reference electrode is located within the ring-shaped auxiliary electrode.