To discuss the mechanisms of infection complications in different degrees after percutaneous nephrolithotomy (pcnL) through predicting and comparing post-pcnL infections based on nomograms, a retrospective cohort study was conducted among 969 cases who underwent PCNL from Dec 5, 2016 to Dec 25, 2017 in Kunming, Yunnan Province. We examined clinical features, urine routine, blood routine, blood biochemistry, imaging studies and operative information and recorded the examination results before surgery for univariate and multivariate logistic regression. We applied receiver operating characteristic curves, calibration curves, accuracy, specificity, sensitivity, positive predictive value and negative predictive value to evaluate and compare the models. Nomograms were used to visualize the different degrees of postoperative infection complications. The risk scores of the three groups were compared by diabetes mellitus distribution. Our results suggest that the more severe the infection is, the more accurate the model predicts and that the occurrence of severe infection mostly is related to the patients' homeostasis. Hence, we developed an online post-PCNL sepsis dynamic nomogram which can achieve visualization and dynamically predict the incidence of sepsis in postoperative patients. Kidney stones, one of the most common urologic diseases, show an upward trend annually 1 , especially in Southwest China where the incidence rate is higher than those in other parts of the country 2. PCNL is used as the standard method in the treatment of upper urinary tract stone > 2 cm 3 with minimal invasion and a faster and higher stone clearance rate 4. However, complications are reported including fever (21.0-32.1%), blood transfusion (11.2-17.5%), extravasation (7.2%) and septicemia (0.3-4.7%) 5. Infection, as a major complication, is graded into fever, systemic inflammatory response syndrome (SIRS), and sepsis according to the severity. Previous studies have reported the risk factors on the severity of infectious complications, such as gender, nephrostomy 6 , preoperative positive urine culture 7 , stone size 8 , age, diabetes mellitus and complex stones 9. Risk factors of SIRS include PCNL operation history, stone size, degree of hydronephrosis, complex stones, preoperative positive urine culture, perfusion pressure, and neurogenic bladder and the use of antibiotics 10-13. Risk factors of sepsis include stone burden, infectious stone, the number of tracts, preoperative positive urine culture, leukopenia, creatinine and operation time 14-17. Nonetheless, most studies only discussed one or two infection outcomes and did not compare similarities and differences of infection concurrency between different degrees in the same samples. In this study, we established models to predict and to study the infection complications of different degrees after PCNL, and compared the differences between the models to illustrate the different infection mechanisms and the clinical significance. Finally, we developed online application to achieve visu...