Abstract: Objective: To investigate the related factors of catheter blockage in children with invasive arterial blood pressure monitoring in pediatric intensive care unit(PICU), and to establish a prediction model. Methods: A total of 267 children in PICU in Peking University First Hospital from January 2018 to December 2022 were selected for invasive arterial blood pressure monitoring via radial artery catheterization. They were divided into blocked group and unblocked group according to whether or not the catheter was blocked. Clinical data of the two groups were collected. Lasso regression and logistic regression were used to screen the relevant factors of catheter blockage in children with invasive arterial blood pressure monitoring in PICU. A Nomogram prediction model was constructed, and calibration curve and receiver operating characteristic(ROC) curve were used to verify the prediction value of this model. Results: Tube sealing fluid by univariate analysis, one-time puncture success, puncture point bleeding, catheter retention time, use of sedative and analgesic drugs, use of mannitol, mechanical ventilation, prothrombin time(PT) and activated partial thromboplastin time(APTT) were the influential factors of catheter blockage in children with invasive arterial blood pressure monitoring in PICU(all P＜0.05).Eight predictors were selected by Lasso regression analysis, including one-time puncture success, puncture point bleeding, catheter retention time, use of sedative and analgesic drugs, use of mannitol, mechanical ventilation, PT and APTT. Logistic regression analysis showed that one-time puncture success, puncture point bleeding, catheter retention time, use of sedative and analgesic drugs, use of mannitol, mechanical ventilation, PT and APTT were the relevant influencing factors of catheter blockage in children with invasive arterial blood pressure monitoring in PICU(all P＜0.05). The concordance index(C-index) and calibration degree of the Nomogram prediction model were 0.945 and 0.928, and it fited well(χ²=8.741, P=0.593). ROC curve analysis showed that the AUC of the model for predicting catheter blockage in children with invasive arterial blood pressure monitoring in PICU was 0.926(95% CI: 0.871-0.984). Conclusion: The factors related to catheter blockage in children with invasive arterial blood pressure monitoring in PICU include one-time puncture success, puncture point bleeding, catheter retention time, use of sedative and analgesic drugs, use of mannitol, mechanical ventilation, PT and APTT. The prediction model constructed by the above factors has reliable prediction value.