The invention discloses a method for isolating dendritic cells, which comprises the following steps: (1) preparation of bone marrow mononuclear cell suspension: taking bone, cutting the epiphysis, washing the middle bone to obtain bone marrow fluid, and cutting the epiphysis until it becomes viscous mixed with the aforementioned bone marrow fluid, placed on a strainer, washed 3 to 4 times to obtain a cell suspension, centrifuged, collected the precipitate, added red blood cell lysate, left standing, centrifuged, washed, and obtained bone marrow mononuclear cells; (2) imDC Cell culture: the bone marrow mononuclear cells obtained in step (1) were resuspended in medium 1, inoculated and cultured, centrifuged, cultured in medium 2 added with growth factors, and cultured continuously for 7 days to obtain imDC cells; (3) mDC Cell culture: Add cell culture medium 3 containing maturation-promoting factors to imDC cells to continue induction culture. The method for isolating dendritic cells of the present invention can effectively separate dendritic cells from mouse bone marrow, and has excellent clinical application prospects.