Triple Negative Breast Cancer (TNBC) is occurred in the mammary gland epithelial malignant tumours, which is easy to recurrence and metastasis. Carcinoembryonic Antigen (CEA) is a kind of glycoprotein, which is widely existed in various human cancer cells. The purpose of this study was to investigate the role of CEA in the prognosis for TNBC patients who received Neoadjuvant Chemoradiotherapy (NCRT). A total 783 TNBC patients and 752 healthy women individuals were enrolled to analyse the prognostic role in the treatment of TNBC. The median follow-up time was 34.5 months. Pathology analysis showed that CEA expression was up-regulated in TNBC tumour tissues. We showed that plasma CEA levels were higher in TNBC patients than healthy individuals. We showed that higher plasma CEA levels were down-regulated in patients received NCRT. Outcomes demonstrated that higher plasma CEA levels presented lower the 5 y Disease-Free Survival (DFS) rates, while lower CEA levels showed a significantly lower 5 y DFS rate (P<0.05). In conclusion, these results indicate that plasma CEA levels were up-regulated in TNBC patients, which suggest that plasma CEA levels are associated with the prognosis of TNBC patients after receiving NCRT.