The invention discloses a treatment system and method for biogas slurry produced from anaerobic fermentation of kitchen waste. The system comprises a filtering and adjusting treatment unit, a coagulating sedimentation treatment unit, an anaerobic treatment unit, a primary nitrification and denitrification treatment unit, a secondary sedimentation tank, a Fenton oxidation treatment unit, a secondarynitrification and denitrification treatment unit, a membrane bioreactor filtration treatment unit, a membrane filtration treatment unit and a sludge treatment unit. The method comprises the main following steps: (1), hydraulic screen sieving and water quality and quantity adjustment; (2), coagulating sedimentation treatment; (3), anaerobic treatment; (4), primary nitrification and denitrification treatment; (5), Fenton oxidation treatment; (6), secondarynitrification and denitrification treatment; (7), membrane bioreactor filtration treatment and (8), membrane filtration treatment. The treatment method is resistant to impact load, the system operates stably, the treatment effect is good, pollutant discharge is greatly reduced, and the method has broad applicationprospect.