The invention discloses a substrate special for sponge city greening and a production method thereof. The substrate comprises, by weight, 3-5 parts of a fermentation product of mushroom residues, vinegar dregs and cassava residues, 2-4 parts of medium and coarse sand, 1-2 parts of carbonized rice husk or plant ash, 2-4 parts of coco coir and 2-3 parts of soil. The particle size of the substrate isnot larger than 50 mm, the unit weight of the substrate is 0.1-0.8 g/cm<3>, the dry density of the substrate is 0.1-0.8 Mg/m<3>, the wet density of the substrate is not larger than 1.2 Mg/m<3>, the total porosity of the substrate is larger than 75%, saturation water absorbency of the substrate is larger than 400%, water-holding porosity of the substrate is larger than 60%, aeration porosity of the substrate is not larger than 20%, the large pore-to-small pore ratio of the substrate is 0.25-0.7, and the pH of the substrate is 5.0-8.0. The production method includes: processing the raw materials, fermenting the raw materials, mixing and stirring, measuring, regulating physical and chemical indexes, packaging in a quantified manner, and the like. The substrate produced by the method is goodin water-holding capacity and water permeability and quite suitable for sponge city greening.