Objectives The requirement of prolonged mechanical ventilation (PMV) is associated with increased medical care demand and expenses, high early and long-term mortality, and worse life quality. However, no study has assessed the prognostic factors associated with 1-year mortality among PMV patients, not less than 21 days after surgery. This study analyzed the predictors of 1-year mortality in patients requiring PMV in intensive care units (ICUs) after surgery. Methods In this multicenter, respective cohort study, 124 patients who required PMV after surgery in the ICUs of five tertiary hospitals in Beijing between January 2007 and June 2016 were enrolled. The primary outcome was the duration of survival within 1 year. Predictors of 1-year mortality were identified with a multivariable Cox proportional hazard model. The predictive effect of the ProVent score was also validated. Results Of the 124 patients enrolled, the cumulative 1-year mortality was 74.2% (92/124). From the multivariable Cox proportional hazard analysis, cancer diagnosis (hazard ratio [HR] 2.14, 95% confidence interval [CI] 1.37-3.35; P < 0.01), no tracheostomy (HR 2.01, 95% CI 1.22-3.30; P < 0.01), enteral nutrition intolerance (HR 1.88, 95% CI 1.19-2.97; P = 0.01), blood platelet count <= 150 x 10(9)/L (HR 1.77, 95% CI 1.14-2.75; P = 0.01), requirement of vasopressors (HR 1.78, 95% CI 1.13-2.80; P = 0.02), and renal replacement therapy (HR 1.71, 95% CI 1.01-2.91; P = 0.047) on the 21st day of mechanical ventilation (MV) were associated with shortened 1-year survival. Conclusions For patients who required PMV after surgery, cancer diagnosis, no tracheostomy, enteral nutrition intolerance, blood platelet count <= 150 x 10(9)/L, vasopressor requirement, and renal replacement therapy on the 21st day of MV were associated with shortened 1-year survival. The prognosis in PMV patients in ICUs can facilitate the decision-making process of physicians and patients' family members on treatment schedule.