Objective To detect the expression of Id1 and p53 in human breast cancer and study their relationship. Methods To choose 80 cases of breast cancer from the surgical department of Tangshan people's hospital. All patients didn't get radiotherapy and chemotherapy before surgery. The expression of Idl and p53 of breast cancer were studied by using SABC immunohistochemistry. Results The expressions of Id1 were found in cytoplasm, while the expression of p53 was found in cell nucleus. The positive rates of Id1 and p53 were 87.5 %(70/80)and 90.0%(72/80) respectively in breast cancer tissues. The expression of Id1 and p53 were significantly higher in breast cancer tissue than those in adjacent non-tumor breast tissues,benign tumor tissues and normal breast tissues(P ＜0.05). The positive rates and expression intensity of Id1 in breast cancer had significant correlation with lymph node metastasis and pTNM stage of the tumor, but had no significant correlation with age, histological differentiation and tumor size. The positive rates and expression intensity of p53 in breast cancer had significant correlation with lymph node metastasis of the tumor, but had no significant correlation with age, histological differentiation,tumor size and pTNM stage. Conclusion Expression of Id1 in human breast cancer is up-regulated. Its expression is associated with lymph node metastasis and TNM stage and represents an independent marker for prognosis of breast cancer. To reduce the expression of Id1 will become the strategy of curing breast cancer. Expression of Id1 and p53 in human breast cancer have the same clinic significance. Each of them can represent an independent marker for prognosis of breast cancer.