The invention provides nanoscale Pickering emulsion type fracturing fluid and a preparing method thereof. The method includes the steps that a water-soluble monomer, two functional monomers, water-soluble polymeric emulsifier and inorganic salt are mixed and dissolved in deionized water to form a water phase; oil-soluble emulsifier and oil are mixed to form an oil phase; the water phase and the oil phase are mixed and heated, nitrogen is introduced, nano particles and an initiating agent are added to initiate polymerization, high-speed dispersion is combined with high-pressure homogenization or high-pressure microjet to disperse a mixed solution into dispersion fluid, the dispersion fluid is diluted to prepare the nanoscale Pickering emulsion type fracturing fluid. The fracturing fluid has good capacity of reducing resistance, aiding discharge, stabilizing clay, suspending sand and reducing surface activity, can effectively reduce usage of clay stabilizer and a discharge aiding agent, reduces operation cost, shortens work time and improves the fracturing efficiency. The stability of the fracturing fluid is effectively improved by the introduced nano particles.