NOVELTY - Recycling piggery sewage comprises (i) homogenizing excrement and anaerobic fermenting, (ii) subjecting anaerobic fermentation biogas slurry to three-stage aeration-oxidation in at least 2 parallely set three-stage oxidation tank, (iii) subjecting aeration-oxidation biogas slurry to primary biodegradation, (iv) allowing the circulation water to flow through aquatic plant and performing secondary biodegradation, and (v) discharging water after secondary biodegradation.    USE - The method is useful for recycling piggery sewage (claimed).    ADVANTAGE - The method: reduces water pressure in water resource shortage area, reduces production cost of fertilizer, and realizes recycling of farming and livestock breeding energy; achieves zero discharge and sustainable development of animal husbandry; and is simple, ensures convenient operation, and is safe.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for piggery sewage recycling system, comprising a homogenizer, a biogas anaerobic fermentation tower, at least 2 parallely set three-stage oxidation tank, aquatic plant field and circulation channel, the homogenizer is connected with the piggery, the homogenizer is connected with the biogas anaerobic fermentation tower through the pipe, the biogas anaerobic fermentation tower is connected with the inlet of the three-stage oxidation tank, the three-stage oxidation tank comprises primary oxidation tank, secondary oxidation tank and tertiary oxidation tank, the tertiary oxidation tank is connected with the aquatic plant field through a pipeline, the aquatic plant field is connected with the circulation channel through water channel, the circulating water channel is multiple horizontal water channels, the adjacent two horizontal water channels are formed at height of 10-20 cm, the horizontal water channel is set with a cage, the circulation water channel is connected with the sedimentation tank, and the sedimentation tank is connected with the discharge area.