An anti-blocking processing system for welding gun nozzles for carbon dioxide arc welding is used for solving the blocking problem of the welding gun nozzles for the carbon dioxide arc welding. The anti-blocking processing system for the welding gun nozzles for the carbon dioxide arc welding comprises a liquid storage tank, a splash-proof liquid spraying device, welding gun placing supports and a PLC (Programmable Logic Controller) control mechanism; the liquid storage tank is filled with splash-proof liquid; a compressed air inlet pipe is arranged at the top of the liquid storage tank; liquid outlet pipes are arranged at the bottom of the liquid storage tank; the splash-proof liquid spraying device comprises a group of splash-proof liquid spraying units which are in series connection with the liquid outlet pipes of the liquid storage tank; the number of the splash-proof liquid spraying units is matched with that of welding guns in welding production lines; movements of the splash-proof liquid spraying units are controlled by the PLC control mechanism; the welding gun placing support is arranged at the tail end of every splash-proof liquid spraying unit. The anti-blocking processing system for the welding gun nozzles for the carbon dioxide arc welding has the advantages of reducing labor intensity of operators, improving welding production efficiency, effectively avoiding the welding gun nozzles from blocking caused by splashing of welding slags and poor electric conduction between a contact nozzle and a welding wire and caused by a processing method of dipping anti-blocking paste and satisfying a workpiece requirement for welding quality.