Objective  To investigate the influential factors of unplanned disembarkation due to clotting in cardiopulmonary bypass line in maintenance hemodialysis (MHD) patients, and to establish a nomogram model of unplanned disembarkation due to clotting in cardiopulmonary bypass line in MHD patients and to validate the nomogram.  Methods  The MHD patients treated in the General Hospital of Shaoxing Second Hospital from April 2022 to June 2023 were retrospectively studied. They were divided into modeling group and validation group with the ratio of 7:3. The clinical data of the modeling group were collected and were then divided into coagulation subgroup and non-coagulation subgroup according to the presence or absence of clotting in cardiopulmonary bypass line. By comparing the clinical data of the two subgroups, multivariate logistic regression was used to analyze the risk factors for clotting in cardiopulmonary bypass line in the MHD patients, and a nomogram model of clotting in cardiopulmonary bypass line in MHD patients was established and validated.  Results  A total of 286 patients were recruited as the study subjects. They were divided into modeling group (n=200) and verification group (n=86) with the ratio of 7:3. The modeling group were divided into coagulation subgroup (n=38) and non-coagulation subgroup (n=162). The incidence of clotting in cardiopulmonary bypass line in MHD patients was 19%. Hypotension (χ2=4.630, P=0.031), prothrombin time (t=2.392, P=0.018), platelet count (t=3.090, P=0.002), hemodialysis for the first time (χ2=4.935, P=0.026), anticoagulation method (χ2=8.546, P=0.014), treatment time (<8h/d, 8-16h/d, >16h/d) (χ2=9.497, P=0.009), blood flow velocity (<200ml/min, ≥200ml/min) (χ2=5.194, P=0.023) and health education before dialysis (χ2=6.991, P=0.008) were statistically different between the two subgroups. Multivariate logistic regression showed that hypotension (OR=3.160, 95% CI: 1.182～8.447, P=0.022), platelet count (OR=1.081, 95% CI: 1.049～1.115, P<0.001), hemodialysis for the first time (OR=3.354, 95% CI: 1.202～9.359, P=0.021), no anticoagulation used (OR=5.845, 95% CI:1.697～20.132, P=0.005), and lack of health education (OR=6.524, 95% CI: 2.322～18.330, P<0.001) were the independent risk factors for clotting in cardiopulmonary bypass line; longer prothrombin time (OR=0.378, 95% CI:0.261～0.547, P<0.001) and blood flow velocity ≥200 ml/min (OR=0.226, 95% CI:0.081～0.625, P=0.004) were the protective factors for clotting in cardiopulmonary bypass line. For verification of the nomogram, the area under ROC curve was 0.891 (95% CI: 0.835～0.947), a better discrimination ability was identified, the maximum approximate entry value was 0.641, the sensitivity was 0.789, and the specificity was 0.852. The theoretical value of calibration curve was in better agreement with the actual value.  Conclusion  This nomogram model of unplanned disembarkation caused by clotting in cardiopulmonary bypass line in MHD patients shows a better efficiency, and provides a reference for clinical practice.