Long non-coding Rnas (lncRNAs) can act as oncogenes or tumor suppressors to regulate cancer development. We found that CYP1B1-AS1 was down-regulated in breast cancer tissues and correlated with the prognosis of patients. Lentiviral vectors were used to overexpress CYP1B1-AS1 in MCF7 cells, and the target proteins bound to CYP1B1-AS1 were detected by pulldown assay and mass spectrometry. The function of CYP1B1-AS1 is unknown. Our study revealed the molecular mechanism of CYP1B1-AS1 inhibiting breast cancer proliferation in breast cancer, and provided a new strategy for the treatment of breast cancer targeting lncRNA.