The invention preparation and application methods of an alkali remover for porous planting concrete. The alkali remover is prepared with slow-release bicarbonate, stearate and sulfite combined with superfine super-pure SiO2 and powdery polycarboxylic acid dispersant or lignosulfonate dispersant; under the action of the dispersant and stearate, it is possible to more sufficiently hydrate cement paste, and a hydration product is more cured; the hydrated calcium hydroxide can react initially with CO2 released by the slow-release salt; by introducing the sulfite, it is possible to exceed the SO4<2-> content of the cement hydration product so that the single-sulfur hydration product is converted into a high-sulfur hydration product; C-S-H can react with SiO2 to generate hydrated calcium silicate having alkalinity less than normal alkalinity so that the alkalinity of the cement hydration product is further reduced, the alkali content of the hydration product is lowered, the alkalinity of the porous planting concrete is lowered, suitable acidity and alkalinity is imparted to the inner structure of the porous concrete, and the growth of plants is benefited.