Objective To investigate the clinical value of white blood cell-to-platelet (WBC/PLT) ratio and related factors in early prognosis evaluation of sepsis. Methods The clinical data of 150 patients diagnosed with sepsis admitted to the emergency intensive care unit (EICU) in Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from June 2018 to June 2020 were prospectively analyzed. According to survival or death, the patients were divided into survival group(n=126) and death group(n=24). The difference of WBC/PLT and clinical and biochemical indexes between two groups in 24 h after onset of sepsis were compared, and the Pearson correlation was used to analyze the correlation between WBC/PLT ratio and risk factors in the patients with sepsis. The Cox regression model was used to evaluate the clinical predictive value of various factors on mortality, and the receiver operating characteristic(ROC) curve was applied to analyze the predictive effect of WBC/PLT ratio on prognosis in the patients with sepsis. Result There was no significant difference in age, gender, infection type and constituent ratio of underlying diseases between the survival or death groups (P>0.05). The proportion of septic shock patients, receiving vasoactive medicines, mechanical ventilation and blood purification in the death group were significantly higher than those in the survival group(P<0.05). The levels of procalcitonin (PCT), urea nitrogen, aspartate aminotransferase (AST), prothrombin time (PT), fibrinogen degradation product （FDP）, D-dimer, pro-brain natriuretic peptide（pro-BNP）and sequential organ failure assessment(SOFA) scores in the death group were significantly higher than those in the survival group. The ratio of WBC/PLT in death group (0.56±1.27) was significantly higher than that in survival group(0.15±0.42)(P<0.05). The Pearson correlation analysis showed that the ratio of WBC/PLT was positively correlated with C-reaction protein(CRP), PCT, urea nitrogen, creatinine, pro-BNP, FDP, and D-dimer(P<0.05). The Cox regression model analysis presented that high WBC/PLT ratio, high urea nitrogen level and high SOFA score were independent risk factors for prognosis in the patients with sepsis (P<0.05). The area under ROC curve of WBC/PLT ratio was 0.643(95% CI: 0.516-0.770, P=0.026), and an optimal cut-off value was 0.186, with sensitivity of 37.5% and specificity of 91.3%. Conclusions The WBC/PLT ratio shows high specificity in the prognosis evaluation of sepsis, which can predict the prognosis of patients early, and is worth to be used in clinical practice.