Objective. The aim of the study is to analyze the clinical characteristics, pathogen distribution, and drug sensitivity information of adult sepsis, and to provide reference for empirical clinical use; to explore the relationship between C-reactive protein (CRP) and calcitonin (PCT) The clinical value in the diagnosis of adult sepsis. Methods. We collected 455 cases of hospitalized patients with positive blood culture, including 352 cases with sepsis and 103 cases without sepsis; 1609 cases of hospitalized patients with suspected infection and negative blood culture, including 287 cases of sepsis, and 518 cases of non-infectious systemic inflammatory response syndrome (SIRS) and 804 cases of local infection. Age, gender, route of admission, admission status, CRP, PCT, and white blood cell (WBC) levels were collected from the patients. The differences between the factors were statistically analyzed, and the receiver operating characteristic curve (ROC curve) was plotted to obtain the optimal cut-off values of CRP and PCT and their area under the curve (AUC), and to compare the CRP, PCT and PCT, and the CRP + PCT tandem to diagnose sepsis sensitivity and specificity. Results. (1) 387 pathogenic strains were isolated from blood cultures of patients with sepsis, 71.06% Gram-negative, 26.87% Gram-positive and 2.07% fungi. (2) Among Gram-positive bacteria, Staphylococcus aureus was 87.5% resistant to penicillin and sensitive to vancomycin, milantropine, and teicoplanin; among Gram-negative bacteria, Escherichia coli was resistant to piracillin The resistance rate was 73.1%, fully susceptible to viraemia (100%) and resistant to imipenem, amikacin, and lacillin/tazole. (3) Among patients with positive blood cultures, CRP and PCT levels were higher in patients with sepsis than in those without sepsis. Pairwise comparison of ROC curves showed that the diagnostic value of PCT was greater than that of CRP (
P
=
0.016
). Conclusion. CRP and PCT have a good reference value for diagnosis of sepsis patients and determination of the degree of infection in septic patients, especially PCT is more valuable for diagnosis of sepsis.