OBJECTIVE： To provide reference for clinical rational drug use in advanced breast cancer patients with grade Ⅳ myelosupression induced by chemotherapy. METHODS： 108 advanced breast cancer patients with grade Ⅳ myelosupression induced by chemotherapy in our hospital from July 2014 to June 2015 were retrospectively analyzed on the characteristics of myelosupression and the reasonability of chemotherapy reguneb and adjuvant drug for myelosupression. RESULTS： The incidence of grade Ⅳ myelosupression induced by chemotherapy in advanced breast cancer patients was 8.3％， chiefly manifesting as grade Ⅳ neutropenia（94.4％）. The chemotherapy regimens which induced grade Ⅳ myelosupression were mainly docetaxel+epirubicin， docetaxel， vinorelbine+lobaplatin； irrational chemotherapy plan mainly shows irrational pretreatment of chemotherapy drug （32 cases， 91.4％）； irrational therapy of myelosupression mainly manifested as rophylactic use of antimicrobials without indication， unsuitable choice of antibiotics （29 cases for each， 36.2％ for each）. CONCLUSIONS： The use of drugs used in advanced breast cancer patients with grade Ⅳ myelosupression induced by chemotherapy is basically rational，yet it is far from perfect in pretreatment of chemotherapy drug and therapy for grade Ⅳ myelosupression， which should be further improved.