The invention relates to a photocatalytic wastewater fuel cell capable of strengthening a free radical reaction. The photocatalytic wastewater fuel cell comprises a photo-anode, a cathode, persistent organic pollutant wastewater, a light source, an electrolyte solution, a quartz reaction pool and an air vent, wherein the photo-anode and the cathode are respectively inserted into the electrolyte solution, which contains the persistent organic pollutant wastewater, in the quartz reaction pool, and are connected by an external circuit; 0.1-0.4mM ferrous ions are added into the electrolyte solution, and the pH value is adjusted to be 1.0-4.0; the cathode is close to the air vent which is continuously filled with air; the light source is turned on for irradiating the photo-anode and the cathode; the ferrous ions have a Fenton-like circular reaction with free radicals and related substances which are generated on the surfaces of the photo-anode and the cathode under the automatic bias effect of the photocatalytic fuel cell, so that the free radical reaction in a system is strengthened, and the performance of the photocatalytic fuel cell is greatly improved. The invention provides a more efficient and economical wastewater treatment and energy recovery method, and has a wide application prospect.