The invention relates to a kitchen waste treatment system and method. The system comprises a kitchen waste digestive system and a biogas slurry treatment system; and the kitchen waste digestive systemcomprises a waste receiving hopper, a bag breaking machine, a manual sorting platform, a spiral lifting conveyor, a crushing pulping machine, a solid-liquid separator, a cyclone desander, a damp hothydrolyzing tank, a three-phase horizontal screw centrifugal machine, a homogeneous pool, a anaerobic digestion tank, a spiral dehydrator, a biogas slurry transfer station, a solid waste collecting device, a biogas purifier, a refining purifying device, a CNG tank and a biogas boiler. According to the kitchen waste treatment system and method, after kitchen waste is subjected to series of treatment, rough grease, biogas, biogas residues and biogas slurry are obtained, the biogas residues and the biogas slurry can be made into organic fertilizers, the rough grease can be made into biodiesel after being processed, the landfill occupied area in the original kitchen waste treatment process is greatly decreased, secondary pollution to the environment is effectively prevented, kitchen waste recycling is achieved, and the good application prospect is realized.