Objective To compare the predictive value of serum albumin (sALB), blood urea nitrogen (BUN) and blood urea nitrogen/plasma albumin (BAR) for 28-day mortality in patients in Trauma Green Channel, and to construct a model for predicting 28-day mortality by combining the Revised Trauma Score (RTS). Methods The clinical data of patients in Trauma Green Channel from January 2020 to December 2020 were retrospectively analyzed to compare the demographic differences, past history, the RTS, the Injury Severity Score, and laboratory results between 28-day survival and death groups. The cut-off values of sALB, BUN and BAR were determined by receiver operating characteristic (ROC) curve, and the area under the ROC curve (AUROC) of sALB, BUN and BAR in predicting 28-day mortality was compared by DeLong non-parametric method. The RTS was combined with each of the above three indicators to construct a prediction model respectively, and the Hosmer-Lemeshow test was used to evaluate the model effect and compare the prediction effect of the models. Results Finally, 419 patients were included, aged 54.3±16.4 years, 309 (73.7%) men, prehospital time 4.0 (2.0-6.0) hours, and 28-day mortality 7.6% (32/419). The ROC curve showed that sALB ≤ 29.5g/L, BUN> 6.97mmol/L and BAR> 7.39mg/g were the cut-off values to predict the 28-day mortality of patients in Trauma Green Channel, and the predictive effect of BRA was better than that of sALB and BUN. RTS-A (RTS+sALB), RTS-B (RTS+BUN) and RTS-BAR (RTS+BAR) were used to construct the predictive models of the RTS combined with sALB, BUN and BAR, respectively. The predictive effect of these three models was better than that of the RTS, and AUROC of RTS-BAR was the largest, but there was no statistical difference between the AUROC of RTS-BAR and RTS-A, and between the AUROC of RTS-A and RTS-B. Conclusion BAR was superior to sALB and BUN in predicting 28-day mortality of patients in Trauma Green Channel, and patients with BAR> 7.39 mg/g indicated poor prognosis. The RTS combined with BAR also has a good value in predicting the prognosis of patients in Trauma Green Channel.