Objective To explore the effect of different doses of Vitamin C on the inflammatory indexes and severity of the patients with pulmonary infectivity of sepsis.Methods The clinical data of 82 patients with pulmonary infectious sepsis admitted to Ganzhou People′s Hospital from February 2017 to December 2019 were retrospectively analyzed.The patients were divided into group A and group B according to the different doses.Patients who received low-dose vitamin C were enrolled in group A (40 cases),and patients who received high-dose Vitamin C were enrolled in group B(42 cases).The central venous pressure (CVP),serum index (lactic acid and vitamin C [VitC]),inflammation indexes (Creactive protein [CRP]and procalcitonin [PCT]),acute physiology and chronic health status scale Ⅱ (APACHE Ⅱ)scores and central venous oxygen saturation (ScvO2) levels were compared between the two groups before treatment and after 7 days of treatment.Results Compared of CVP,serum VitC,lactate level,CRP,PCT,APACHE Ⅱscore,ScvO2 between the two groups before treatment,and the comparison of CVP,serum VitC,lactate levels,CRP,PCT,APACHEⅡ,ScvO2 between the two groups after 7 days of treatment,the differences were not statistically significant (P>0.05).After 7 days of treatment,the levels of CVP,serum VitC and ScvO2 in both groups were higher than those before treatment,and the scores of lactic acid,CRP,PCT and APACHE Ⅱwere lower than those before treatment,and the differences were statistically significant (P<0.05).Conclusion Vitamin C adjuvant therapy for patients with pulmonary infectivity of sepsis can increase the VitC content in the body,correct the patient′s hypotension and acidosis,reduce the body′s inflammatory response level,improve the patient′s blood oxygen content and lung function,reduce the severity of the disease,and the effect of large or small doses is equivalent.