Abstract: Breast carcinoma does harm to woman health severely, and its rate of incidence tends to be higher gradually in the world. The study showed that the expression of MUC1 and HER2 genes reveals some biological characters of breast carcinoma. MUC1 and HER2 genes were closely associated with the occurrence, metastasis and prognosis of breast cancer. MUC1 gene was expressed abnormally in the breast cancer. The product encoded by MUC1 gene was the important carcinoma marker, and MUC1 gene has always been a sign of checking lymph metastasis in breast cancer. HER2 gene was expressed highly in tumor and lowly in normal tissues, which has been regarded as an independent prognosis marker for breast cancer. The overexpression of HER2 in the breast cancer showed that the potency of metastasis was high. With development of the study, HER2 has been regarded as a gene therapeutic target for breast cancer. Herceptin had been proved to improve treatment outcomes in breast cancer, but target therapy of MUC1 gene was working on the experiment. We summarize the function of MUC1 and HER2 on gene localization, constitution, performance in breast cancer, so we can deeply recognize physiology and pathophysiology functions of these genes and their expression product, which are beneficial to diagnosis and therapy of breast cancer.