The invention discloses a method for clean production of DTDC (1,1'-dithiobis[hexahydro-2H-azepin-2-one]). The method comprises the following steps: enabling caprolactam and sulfur monochloride to react in a bad solvent of DTDC, heating the reaction liquid obtained from the reaction until DTDC is completely dissolved but caprolactam hydrochloride is not dissolved, and performing filtering while being hot; crystallizing the filtrate obtained from filtration so as to obtain DTDC; and performing pyrolysis on filter cakes obtained from filtration, so as to obtain caprolactam. Through selection ofthe solvent and change of aftertreatment modes, no water phase is introduced into the whole post-treatment process, so that generation of wastewater can be prevented substantially. By adopting the method, the recovery rate of caprolactam is high, the production cost is lowered, and the problems of severe waste of caprolactam and difficult wastewater treatment are solved. Compared with a conventional production process, the method is low in production cost, is free of wastewater after reactions are completed, and is safe for the environment.