Abstract: Objective To investigate the expression of mRNA of aspartyl/asparaginyl beta-hydroxylase (ASPH) gene in invasive breast cancer (IBC) and the relationship between methylation of gene promoter and clinicopathological parameters. Methods In 91 cases of breast cancer tissues and matched normal tissues (MNT), mRNA expression of the ASPH gene was detected by reverse transcription of real-time fluorescence quantification PCR and the methylation status of CpG island in the ASPH gene promoter region was detected by methylation specific PCR (MSP).And the relationship between the expression and the clinicopathological features of breast cancer was analyzed. Results The expression of ASPH gene mRNA in IBC was significantly higher than that in MNT (P<0.001).The fold change of ASPH mRNA expression was related to whether E-cadherin was positive (r=0.195,P=0.041).The positive rate of methylation of ASPH gene promoter in breast cancer and MNT was 47.3% (43/91) and 89.0% (81/91). The methylation rate of gene promoter was correlated with E-cadherin and tumor size (P<0.05). Conclusion The mRNA expression and promoter methylation rate of ASPH gene may play a role in the development and progression of breast cancer.