Objective To study the expression of tumor abnormal protein (TAP) in different types of breast cancer patients and explore its clinical value. Methods Eighty-four patients of breast cancer diagnosed by surgery in our hospital from 2014 to 2016 were selected. The area of TAP aggregates in peripheral blood smear was detected. The difference of TAP expression was compared among the patients with different clinicopathological characteristics, and the clinical value of TAP in diagnosis and treatment of breast cancer was analyzed. Results The expression of TAP in the patients ≥ 65 years of age was significantly higher than that of the patients <65 years (P < 0.05). The TAP expression of the patients with lymph node metastasis was also significantly higher than that of the patients without lymph node metastasis (P < 0.05). However, there was no significant difference in the TAP level among the patients with different expressions of ER, PR and HER-2 (P > 0.05). Conclusions The expression of TAP in breast cancer patients with different age and different lymph node metastatic status is significantly different. Detection of TAP has important clinical value.