The invention provides hollow plastic spheres, and a preparation method and an application thereof. The hollow plastic spheres are in hollow structure, with an average particle size of 1-300 [mu]m. The plastic comprises 0.1-100% by weight of polycarbonate and the balance being polystyrene. The hollow plastic spheres are prepared by the steps of dissolving an oil-phase solute in an organic solvent, adding a foaming agent, mixing uniformly to obtain an oil phase, wherein the oil-phase solute is the above amount of polycarbonate or a mixture of polystyrene and/or styrene monomers and the above amount of polycarbonate; dissolving a dispersing agent or the dispersing agent and an emulsifying agent in water to obtain a water phase; mixing the oil phase and the water phase uniformly, so as to make the oil phase dispersed uniformly in the water phase to obtain an emulsion; heating the emulsion to evaporate the organic solvent while curing and foaming the oil-phase droplets; then performing liquid-solid separation on the emulsion, and drying the solid phase. The hollow polystyrene plastic spheres have small and controllable particle size, and can be applied in the fields of petroleum drilling fluids, cosmetics, coatings, etc.