The invention relates to the technical field of organic agriculture, in particular to a water and fertilizer integrated system and method for organic cultivation. The water and fertilizer integrated system for organic cultivation comprises a control system, an irrigation system, an organic liquid fermentation system and a fertilizer application system, wherein the irrigation system, the organic liquid fermentation system and the fertilizer application system are in communication connection with the control system, the irrigation system comprises a water source, a main irrigation pipeline, an irrigation water pump, a first water injection pipeline, a second water injection pipeline and an irrigation electromagnetic valve, and the irrigation water pump, the first water injection pipeline, the second water injection pipeline and the irrigation electromagnetic valve are sequentially arranged on the main irrigation pipeline; the organic liquid fermentation system comprises a fermentation tank, a circulation pump and a stirrer; the fertilizer application system comprises a liquid mixing tank, a fertilizer sucker, a liquid storage tank, a fertilizer application pipeline, a fertilizer application water pump, a first liquid distribution pipeline and a fertilizer application electromagnetic valve, and the fertilizer application water pump, the first liquid distribution pipeline and the fertilizer application electromagnetic valve are sequentially arranged on the fertilizer application pipeline. The water and fertilizer integrated system for organic cultivation integrates the organic liquid fermentation system with the water and fertilizer integrated technology, can realize intelligent and fine management of water and fertilizer for organic cultivation crops, and largely improves labor production efficiency.