The invention relates to a photochromic water-based ink for textiles, and a preparation method and an application thereof. The photochromic water-based ink is prepared from a weather-proof photochromic microcapsule powder, an adhesive, a cross-linking agent, a dispersing agent, a wax emulsion, a leveling agent, a film-forming agent, a penetrating agent, a pH regulator, an antifoaming agent, an antioxidant, a preservative, a thickener and deionized water. The photochromic water-based ink for textiles makes up the defects of a commercially available photochromic oily system, realizes zero TVOC emission, meets the requirements of ecological environmental protection, makes up the defects of a commercially available photochromic aqueous system, and has the characteristics of uniform dispersion,long storage time, good stability, excellent washability, high drying speed and good processing continuity.