The invention provides a clean-water carrying fracturing supporting agent. The supporting agent is prepared by coating and modifying macromolecule polymer particles. A monomer solution, a crosslink agent, an initiator and rock ore material powder are synthesized in an aqueous solution with dissolved dispersing agent to obtain the macromolecule polymer particles. The invention also provides a method for preparing the supporting agent. The breaking rate of the clean-water carrying fracturing supporting agent is less than 2 percent under the pressure of 52MPa, the volume density is 0.61 to 0.68 g/cm<3>, the apparent density is 1.02 to 1.25 g/cm<3>, the density is close to that of the water, and water or salted water can be used as a sand carrying liquid in the application process of the supporting agent, so that the fracturing construction cost can be greatly reduced, the energy conservation and emission reduction can be achieved, the macromolecule assistant such as guar gum can be avoided, and the environmental pollution can be reduced.