Objective To develop and validate a nomogram prediction model for pulmonary infection in patients following cardiac valve replacement surgery, providing a reference for early screening of high-risk populations and implementing targeted preventive measures. Methods Clinical data of patients who underwent cardiac valve replacement surgery at the Second Affiliated Hospital of Anhui Medical University from January 2020 to October 2023 were collected. Patients were randomly assigned to a modeling group and a validation group in a 7 : 3 ratio. Based on the occurrence of pulmonary infection post-surgery, patients were divided into a pulmonary infection group and a non-pulmonary infection group. Risk factors for pulmonary infection after cardiac valve replacement were analyzed using least absolute shrinkage and selection operator (LASSO) regression and logistic regression to establish a risk prediction model, which was subsequently validated. Model evaluation was conducted using the area under the receiver operating characteristic curve (AUC), calibration curves, and decision curve analysis. Results A total of 689 patients were included, comprising 354 males and 335 females, with a mean age of (57.37±12.76) years. The incidence of pulmonary infection was 16.0% (110/689). Independent risk factors for pulmonary infection following cardiac valve replacement included emergency admission, smoking history, chronic obstructive pulmonary disease, duration of cardiopulmonary bypass, duration of tracheal intubation, and postoperative renal injury. The AUC for the modeling group was 0.911 [95%CI (0.877, 0.946) ], with a Hosmer-Lemeshow χ2-value of 6.577 (P=0.583) in the training group. The AUC value was 0.891 [95%CI (0.840, 0.941) ], with a Hosmer-Lemeshow χ2-value of 5.486（P=0.705）in the validation group. The model demonstrated good discrimination, calibration, and net benefit. Conclusion The established nomogram prediction model has significant predictive value and can be applied to risk assessment and individualized treatment for pulmonary infection in patients following cardiac valve replacement surgery.