Objective: To detect the circulating tumour cells in peripheral blood of patients with breast cancer, discuss their correlations with molecular typing and clinical characteristics of patients and investigate their clinical application value. Methods: A total of 160 patients with breast cancer diagnosed in our hospital from July 2015 to July 2016 were enrolled, and 40 patients with benign breast disease were selected as the control group. TM-i-FISH was used to detect circulating tumour cells (CTCs), combined with molecular typing and clinical feature identification of breast cancer. The corresponding entry point was calculated, and the number of CTCs detected was determined. Results: After comparing the sensitivity and specificity of deferent entry points, the entry point of 2.5 was the best, which had a sensitivity of 0.492 and specificity of 0.897. Therefore, more than 3 CTC-positive indexes was taken as positive in this study. The results indicated that 24 patients were CTC positive in stages I and II, 13 patients were positive in stage III, and 17 patients were positive in stage IV. The difference between groups was statistically significant (P < 0.05, chi 2 = 7.848, P = 0.020). Sixty-four patients with stage M1 distant metastasis were positive, and the positive rate was significantly higher than that of stage M0 (P < 0.05, chi 2 = 6.181, P = 0.009). There was no significant difference in CTC positivity between primary tumour stage and regional lymphatic metastasis groups (P > 0.05). Moreover, there was no significant difference in CTC positivity between oestrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 expression groups (P > 0.05). Conclusion: There is no significant correlation between CTCs and molecular typing of breast cancer, but CTCs are closely related to the clinical typing and metastasis of breast cancer. Therefore, CTC detection is helpful for evaluating the early development of breast cancer.