The invention relates to the technical field of diphenyl guanidine (DPG) production and specially discloses a method for reducing wastewater generation in a producing process of an accelerant of DPG. The method for reducing wastewater generation in the producing process of the accelerant of the DPG is characterized in that DPG product washing water is utilized as ammonia preparation absorption water to be prepared into ammonium hydroxide; the ammonium hydroxide, CA and catalyst are added into an oxidizing kettle to be stirred and heated; oxygen begins to be introduced into the oxidizing kettle when temperature in the oxidizing kettle is 64+/-2 DEG C, and oxygen stops being introduced when reaction reaches a destination. The method disclosed by the invention is simple to operate, is easy to industrialize, has no effect on product quality, reduces DPG wastewater discharge by 60% or more, greatly reduces the wastewater generation amount, reduces water treatment pressure and is beneficial to environmental friendliness.