Provided in the present invention are a pH-responsive nano-gel plugging material, and a preparation method therefor and the use thereof. The pH-responsive nano-gel plugging material comprises the following raw materials in parts by mass: 50-70 parts of water, 2-3 parts of an emulsifier, 25-35 parts of an acrylic terpolymer, 10-15 parts of a polyalcohol compound, and 10-20 parts of a vinyl pyridine compound. The pH-responsive nano-gel plugging material can be applied to the plugging of Ordovician carbonate rock fractures and micro-karst cave strata, and can automatically identify Ordovician carbonate rock fractures and micro-karst cave leaking layers and realize effective blocking thereof.