The invention belongs to the field of leak stopping of using a drilling fluid, and discloses a shearing responding gel plugging agent, which comprises a polymer composite monomer, a solid organic macromolecular crosslinking agent, a first initiator, a rheological regulating agent, and a flexibilizer. The invention also discloses a preparation method of the gel plugging agent. The preparation method comprises following steps: (I) adding the polymer composite monomer and the solid organic macromolecular crosslinking agent into clean water, and stirring to obtain a mixed solution (a); (II) addingthe rheological regulating agent into the mixed solution (a), and stirring to obtain a mixed solution (b); (III) adding the flexibilizer into the mixed solution (b), and stirring to obtain a mixed solution (c); (IV) adding the first initiator into the mixed solution (c), and stirring to obtain a mixed solution (d); and (V) sealing the mixed solution (d), and allowing the mixed solution (d) to stand still to carry out curing and gelling to obtain the shearing responding gel plugging agent. The gel plugging agent has the characteristics of proper shearing responding property, anti-diluting performance, and gelling strength, and has weak gravity settling phenomenon.