The invention discloses a mineral preselection method of weakly magnetic ore. The method comprises the following steps of: (1) screening raw ore before grinding and screening out ore with the grade of -2mm; (2) selecting the screened ore with the grade of -2mm with a low-intensity separator, wherein the concentrate enters the grading process, and the weakly magnetic tailings directly enter a strong-intensity separator for strong-intensity separation; and (3) enabling the strongly magnetic concentrate selected by the strong-intensity separator to enter the grading process and using the strongly magnetic tailings as final tailings. The preselection method provided by the invention prevents the metal loss of weakly magnetic tailings in the concentration process, simplifies the process flow, can preselect the weakly magnetic ore with low grade, fine embedding granularity and easy argillization characteristic by adopting the process, realize preliminary tailing removal and improve the grinding grade so that the aim of greatly improving the yield is achieved.