Objective To analyse the factors that lead to venous thrombosis among breast cancer patients who need totally implantable access port(TIAP) for chemotherapy. Methods Collecting the clinical data of 60 breast patients admitted to Guanzhou First People's Hospital from May 2018 to April 2019, analysed with SPSS 26.0. Results Catheter-related thrombosis(CRT) occurred in 21 out of 60(35%) patients with TIAP. 30.3% patients with BMI≤24 and 40.74% patients with BMI＞24 had CRT, and incidences of CRT were 20%, 33.34%, 44.12% at the fourth, sixth, eighth therapy respectively. The access terminal position at T5-T8 had 66.67%, 26.09%, 28.57%, 50% of incidence for CRT respectively. 27.5% CRT was with high Ki-67 expression and 50% CRT was with low Ki-67 expression; 47.62% patients with polyurethane catheter and 28.21% patients with silicone catheter got CRT. There were no significant differences in the comparisons above. CRT incidence in ER/PR negative patients was 60%,while 23.08% in ER/PR positive patients (P＜0.05). In HER-2 positive and negative patients, the incidences of CRT were 50% and 23.53% (P＜0.05). Logistic regression noticed that ER/PR negative would increase the incidence of CRT(OR=4.482, 95%CI:1.116～17.998, P＜0.05), low Ki-67 expression would accelerate CRT(OR=7.051, 95%CI:1.513～32.858, P＜0.05). There was no significant difference in the formation of CRT with HER-2 expression(OR=0.254, 95%CI:0.058～1.115, P＞0.05). Conclusion CRT was a common complication of TIAP, which related with ER/PR expression, and should pay attention to during clinical practices.