〔Abstract〕 Objective To provide a new monitoring index for clinical diagnosis and prognosis evaluation of breast cancer, and to provide a guiding theoretical basis for further research and treatment program formulation of breast cancer by studying the expression of Cbl Proto-Oncogene C(CBLC) in breast cancer. Methods The gene expression spectrum matrix(FPKM) of 1104 breast cancer tissues and 113 adjacent tissues were downloaded from TCGA of USCS Xena(https://xenabrowser.net). The expression differences of CBLC gene in breast cancer molecular classification, histopathological type, TNM stages and tumor stages and the relationship of prognosis were analyzed. The expression of CBLC in 30 tumor tissues or para-carcinoma tissues were observed by immunohistochemical staining. MCF7 breast cancer cells were used for scratch test, Transwell test and CCK-8 test, and the effects of CBLC on proliferation and migration were observed. Results The expression level(P=2.31×10-20) and H-Score(P=0.014)of CBLC in the breast cancer group was higher than that in the para-carcinoma group. CBLC expression in Luminal A(P=1.68×10-4) and mucinous carcinoma(P=4.00×10-5) breast cancer was the highest among different breast cancer molecular types(P=1.68×10-4). The expression level of CBLC decreased from stage Ⅰ to stage Ⅱ in breast cancer(P=0.049 4). The survival rate of breast cancer patients in the high CBLC expression group was higher than that in the low CBLC expression group on a median basis(P=0.054). The high expression group of CBLC could inhibit the proliferation and migration of breast cancer cells. Conclusion The expression of CBLC in various breast cancer types and stages is significantly different, and it mainly expresses in Luminal A breast cancer which is low malignant molecular type, mucinous carcinoma which is high differentiated histopathological type and early breast cancer. It is positively correlated with survival and prognosis of breast cancer patients, and it can inhibit the migration and proliferation of breast cancer. CBLC may be a potential target for new molecular diagnosis or targeted treatment of breast cancer.