Objective: Critically ill patients with solid tumors complicated with paraneoplastic pemphigus are usually treated in intensive care units (ICU) for perioperative management after surgical treatment. In this study, the clinical characteristics and predictors of long-term prognosis of these critically ill patients were analyzed. Methods: the clinical and laboratory data of 63 patients with solid tumors complicated with paraneoplastic pemphigus admitted to ICU from 2005 to 2020 were retrospectively analyzed, and the survival status of the patients were followed up. Results: Among the 63 patients, 79.4% had Castleman disease as the primary tumor, and 20.6% with other pathological types; 69.8% had severe-extensive skin lesions, and 30.2% had other skin lesions; the patients with bronchiolitis obliterans accounted for 44.4%, and 55.6% were not merged. Postoperative fungal infection occurred in 23.8% of the patients, and 76.2% without fungal infection. The median follow-up time was 95 months, and 25 patients died during the study period. The 1-year, 3-year and 5-year survival rates were 74.6% (95%CI 63.8%-85.4%), 67.4% (95%CI 55.6%-79.2%) and 55.1% (95%CI 47.9%-62.3%), respectively. The log-rank univariate analysis showed that the patients had age>40 years (P=0.042), preoperative weight loss>5 kg (P=0.002), preoperative albumin < 30 g/L (P < 0.001), paraneoplastic pemphigus complicated with bronchiolitis obliterans (P=0.002), and perioperative fungal infection (P < 0.001) had increased mortality. Cox univariate analysis showed that preoperative weight loss >5 kg (P=0.005), preoperative albumin < 30 g/L (P < 0.001), paraneoplastic pemphigus complicated with bronchiolitis obliterans (P=0.009), preoperative bacterial pulmonary infection (P=0.007), prolonged surgical time (P=0.048), postoperative oxygenation index (P=0.012) and low albumin (P=0.010) and hemoglobin concentration (P=0.035) in ICU, acute physiology and chronic health evaluation (APACHE Ⅱ) score (P=0.001); sequential organ failure assessment (SOFA) score (P=0.010), and postoperative fungal infection (P < 0.001) were risk factors for long-term survival. Cox regression model for multivariate analysis showed that preoperative weight loss > 5 kg (HR 4.44; 95%CI 1.47-13.38; P=0.008), and preoperative albumin < 30 g/L (HR 4.38; 95%CI 1.72-11.12; P=0.002), bronchiolitis obliterans (HR 2.69; 95%CI 1.12-6.50; P=0.027), and postoperative fungal infection (HR 4.85; 95%CI 2.01-11.72; P < 0.001) were independent risk factors for postoperative mortality. Conclusion: The 5-year survival rate of critically ill patients undergoing surgery for paraneoplastic pemphigus combined with solid tumors is approximately 55.1%, with preoperative weight loss > 5 kg, albumin < 30 g/L, bronchiolitis obliterans and postoperative fungal infection were associated with an increased risk of near- and long-term postoperative mortality.