The invention discloses a method of coupling and denitrification integrated treatment by taking fermented septic tank sludge as a carbon source, and belongs to the technical field of wastewater treatment. A system mainly comprises an anoxic/aerobic/anoxic/aerobic integrated device and a sludge fermentation tank. Sewage enters the integrated device, reactions of anoxic denitrification, aerobic nitrification, anoxic denitrification and aerobic removal of rest organic matter are sequentially performed, and sludge fermentation liquor provides the carbon source. The method is applicable to small-sized wastewater treatment, the targets of resoureilization and minimization of sludge treatment are realized through in-place fermentation of septic tank sludge to form the carbon source, and meanwhile, the carbon source is provided for denitrification, therefore, the method has two functions.