The invention discloses a low temperature continuous denitrification process for coke oven smoke and reactor thereof. The reactor is divided into 2-9 individual regions, in between the regions are installed with heat insulation facilities, inside each of the regions are arranged with denitrification catalyst, a rectification grille, a soot blower, a pressure difference transmitter, an air inflow pipe for coke oven smoke, and more. When ammonium bisulfate, ammonium sulfate and other sticky substances generated by the reaction of SO2 and NH3 in the oven smoke, consolidate by large amount on the catalyst surface, causing the drop of catalyst activity in certain region of the reactor, the air intake valve is closed for smoke in the associated region, and hot air supply is plugged into the associated region, speeding up the decomposition by heat of ammonium bisulfate, ammonium sulfate and other substances, the denitrification catalyst is regenerated, with no effect on the running of denitrification devices in the remaining regions. The present invention is simple to operate, safe and reliable, with less area occupied, and low operating cost.