The invention provides a kitchen waste fermentation wastewater treating method which is used for treating wastewater produced from kitchen waste slurry after anaerobic digestion and dewatering and wastewater produced in other procedures of kitchen waste treatment. The wastewater is subjected to oil-separation primary sedimentation, water quantity and water quality regulation, A / O biochemical treatment, sedimentation treatment, treatment in a first coagulative sedimentation tank, treatment in a Fenton reactor, treatment in a second coagulative sedimentation tank and treatment in a biological aerated filter in sequence. With adoption of the method, pollutants such as COD (chemical oxygen demand), BOD5 (biochemical oxygen demand), SS (suspended solids) and the like in the wastewater are removed effectively, TN (total nitrogen) and TP (total phosphorus) can be removed effectively, wastewater chroma can be reduced effectively, TN and TP removal rate is increased, and the pollutants such as COD, BOD5, NH3-N, TP and the like in the treated wastewater as well as the chroma of the treated wastewater can stably meet requirements of level-1 in the integrated wastewater discharge standard (GB8978-1996).