Objective To establish a quick method to identify BMSC by fast violet B salt staining and evaluate the clinic value. Methods Smears of separated and cultured BMSC, bone marrow, pleural and ascitic fluids were made, then the staining of fast violet B salt was performed. The BMSC in aplastic anemia (AA), high hyperplasia and normal groups were counted and compared with each other. Meanwhile, the diagnostic value of this method to AA was evaluated. Results The cytoplasm of BMSC presented mauve, while the nucleus were negative, other cells such as myelocytes, nucleated erythrocytes, megakaryocytes, monocytes, macrophages, lymphocytes and plasmacytes were negative. The count of BMSC in AA, high hyperplasia and normal group was 1.07 ± 0. 29, 2. 26 ± 0. 37 and 1.58±0. 33, respectively. Significant differences were found between AA and high hyperplasia groups, AA and normal groups, high hyperplasia and normal groups, respectively (P < 0.01). The sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of this method for diagnosis of AA were 90%, 93%, 12. 86 and 0. 11,respectively. Conclusions The fast violet B salt staining is simple and convenient. It could be used to identify BMSC and play an important role in judging the hyperplasia extent and differentiation of AA.