To explore the significance of neutrophil CD64 (nCD64), interleukin-6 (IL-6), and procalcitonin (PCT) alone and in combination in the diagnosis and prognosis evaluation of patients with sepsis. A prospective study was conducted. Adult patients admitted to the Western Intensive Care Unit (ICU) of Yantai Yuhuangding Hospital Affiliated to Medical College of Qingdao University from September 2020 to October 2021 were selected as subjects. The venous blood of the selected patients was collected within 6 hours of entering the ICU to measure the levels of nCD64, IL-6 and PCT. The levels of nCD64, IL-6 and PCT of septic patients were measured again on the 3rd and 7th days after admission to ICU. According to the diagnostic criteria of Sepsis-3, the patients were divided into sepsis group and non-sepsis group to evaluate the diagnostic value of nCD64, IL-6 and PCT in sepsis. The patients with sepsis were divided into sepsis group and septic shock group according to their condition on admission to ICU, and the evaluation value of three biomarkers for sepsis was evaluated. Sepsis patients were divided into the survival group and the death group according to survival after 28 days, and the relationship between the three biomarkers and the prognosis of sepsis was evaluated. Finally, 47 patients with sepsis, 43 patients with septic shock, and 41 patients without sepsis were enrolled. Seventy-six patients with sepsis survived and 14 died after 28 days. (1) The levels of nCD64, IL-6 and PCT on the first day of ICU admission in the sepsis group were significantly higher than those in the non-sepsis group [nCD64: 26.95 (14.05, 86.18) vs. 3.10 (2.55, 5.10), IL-6 (ng/L): 93.45 (52.73, 246.30) vs. 34.00 (9.76, 62.75), PCT (μg/L): 6.63 (0.57, 68.50) vs. 0.16 (0.08, 0.35), all P < 0.01]. The receiver operator characteristic curve (ROC curve) showed that the area under curve (AUC) of nCD64, IL-6 and PCT in the diagnosis of sepsis were 0.945, 0.792 and 0.888, respectively. The diagnostic value of nCD64 was the highest. When the cut-off value of nCD64 was 7.45, the sensitivity and specificity were 92.2% and 95.1% respectively. When nCD64, IL-6 and PCT were diagnosed in pairs or in combination, the combination of the three had the highest diagnostic performance, with AUC of 0.973, sensitivity of 92.2% and specificity of 97.6%. (2) The levels of nCD64, IL-6 and PCT in septic shock group were higher than those in sepsis group on the 1st, 3rd and 7th day after admission to ICU. ROC curve analysis showed that nCD64, IL-6 and PCT had some accuracy in evaluating the severity of sepsis on the 1st, 3rd and 7th day after entering ICU, with AUC ranging from 0.682 to 0.777. (3) The levels of nCD64, IL-6 and PCT in the death group were significantly higher than those in the survival group. Except for the nCD64 and PCT values on the first day after admission to the ICU, there were significant differences between the two groups in all indicators at other time points. ROC curve analysis showed that the AUC of nCD64, IL-6 and PCT predicting the prognosis of sepsis at each time point ranged from 0.600 to 0.981. The clearance rates of nCD64, IL-6 and PCT at 3 and 7 days after ICU admission were calculated by dividing the difference between the 1st and 3rd or 7th days after entering the ICU by the value at the 1st day. Logistic regression was used to analyze their predictive value for the prognosis of sepsis. The results showed that the clearance rates of nCD64, IL-6 and PCT on the 3rd and 7th day of ICU were protective factors for 28-day mortality in patients with sepsis, except the clearance rate of IL-6 on the 7th day. nCD64, IL-6 and PCT have good value as biomarkers for the diagnosis of sepsis. The diagnostic value of nCD64 is higher than that of PCT and IL-6. When they are used together, the diagnostic value is the highest. nCD64, IL-6 and PCT have certain value in evaluating the severity and predicting the prognosis of patients with sepsis. The higher the clearance rate of nCD64, IL-6 and PCT, the lower the 28-day mortality risk of patients with sepsis.