The invention discloses a preparation method of high-fluidity TiO2 and an organic surface treatment mechanism thereof and belongs to the technical field of TiO2 preparation. The preparation method comprises the following steps: 1, a titanium dioxide crude product is ground and dispersed; 2, inorganic surface treatment is carried out on slurry; 3, suction filtration and washing are carried out on the slurry by the use of deionized water, and the slurry is dried; 4, a cavity in a high-temperature bag filter is preheated, steam pressure is controlled, and steam is conveyed to the high-temperature bag filter; 5, when temperature in the cavity reaches 200-300 DEG C, steam temperature is controlled to 280-300 DEG C; 6, when temperature in the cavity reaches 140-160 DEG C, thermal insulation is carried out on the high-temperature bag filter; and 7, 40-60% of an organosilicone surface treating agent is added into a jet mill, and the dosage is 0.3-0.5 percent; and simultaneously, feeding is conducted to carry out organic surface treatment. In the stage of jet pulverization, organosilicon (silicone oil) is selected to be added so as to carry out organic surfactant coating on TiO2, and by lubrication effect and low surface energy of organosilicon, high fluidity is achieved at macro level.