Accurate prognostic assessment of critically ill trauma patients in emergency departments is crucial for early intervention and improving survival rates. This study investigates the relationship between blood parameters, disease severity, and patient outcomes. To explore the relationship between blood parameters and the severity and prognosis of critically ill trauma patients in an emergency trauma center. The goal is to facilitate early diagnosis, implement measures to improve survival rates, and enhance patient outcomes. This retrospective study analyzed the blood parameters of 569 critically ill trauma patients admitted to the trauma center from 2020 to August 2023. The analysis focused on examining the relationship between these parameters and the severity and prognosis of the patients. Compared to the improved and non-recovered groups, the mortality group had longer times from injury to hospital admission, higher ISS and NEWS scores, lower GCS scores, more acidic blood gas analysis, electrolyte imbalances, and poorer liver and kidney function as well as coagulation indicators. Low pH, high PaCO2, high lactate, high potassium, high NLR, high D-Dimer, high ISS, and high NEWS are independent risk factors. Conversely, high PLT, albumin, and GCS scores are independent protective factors. These indicators can effectively predict the prognosis of trauma patients.