The invention discloses a preliminary classification, ore grinding classification and separated flotation combined process of collophanite and a system of the process, and relates to the technical field of collophanite beneficiation. Wet sieve classification equipment classifies raw ore according to the particle size of 0.2 mm, fine particles of -0.2 mm are separated out in advance, only particleswith the grade being +0.2 mm enter a mill for ore grinding, qualified-grade particles entering the mill are reduced, the phenomenon of over grinding in the mill is reduced, the service life of the mill is prolonged, and therefore the treatment capacity of the mill is improved. After pre-classified products with the grade being -0.2 mm are classified again, the parts with the grade being +0.074 mmenter a two-stage mill for ore grinding, finally, qualified ore grinding products are formed to enter the independent flotation process, and the parts with the grade being -0.074 mm enter the independent flotation process. The particle size of native fine silt is generally smaller than 5 micrometers, and consequently most fine silt exists in ore with the grade being -0.074 mm. Thus, large-silt-content ore with the grade being -0.074 mm and small-silt-content ore with the grade being +0.074 mm in the raw ore are subjected to separated flotation, the sorting effect is improved, and meanwhile reagent consumption can be reduced.