Abstract: OBJECTIVE To explore the clinical detection value of inflammatory factors and cytokine levels in patients with secondary infection of liver failure. METHODS A total of 120 patients with liver failure treated in the affiliated hospital of Chengde medical university from Jan. 2016 to Dec. 2018 were selected as study subjects, and were divided into 51 cases of secondary infection group and 69 cases of non-infected group according to whether secondary infection. After admission, both groups received routine treatments such as nutrition support, hepatocyte growth-promoting factors, and electrolyte maintenance. Fasting venous blood was drawn in two groups at the time of admission and in the secondary infection group when a typical infection occured. Blood procalcitonin（PCT）, anti-inflammatory factors(transforming growth factor-β（TGF-β）, interleukin-10（IL-10）, interleukin-17（IL-17）, pro-inflammatory factor C-reactive protein（CRP）, tumor Necrosis factor-α（TNF-α）, interleukin-6（IL-6）, and liver function indicators（alanine aminotransferase（ALT）, direct bilirubin（DBil）, total bilirubin（TBil）; T lymphocyte subsets CD₄⁺, CD₈⁺） were detected. RESULTS The PCT level at the time of diagnosis in the secondary infection group was（2.12±0.57） ng/ml, significantly higher than that in the non-infected group（0.28±0.24） ng/ml（P＜0.001）. The levels of CRP（30.78±5.42）mg/L, IL-6（41.87±8.29）ng/L and TNF-α（425.83±35.92）mg/L at the time of diagnosis in the secondary infection group were significantly higher than those of the Non-infected group（P＜0.001）. The TGF-β（148.52±20.27） mg/L, IL-10（97.38±10.14）mg/L and IL-17（228.79±17.68）ng/L in the secondary infection groupat the time of diagnosis were decreased and significantly lower than those in non-infected group（P＜0.001）. The level of CD₄⁺（27.69±4.07）% and CD₄⁺/CD₈⁺（0.81±0.12） levels in the secondary infection group at the time of diagnosis were significantly lower than those in the non-infected group. The level of CD₈⁺ was（36.84±6.92）%, significantly higher than that in the non-infected group（P＜0.001）. The levels of ALT（217.65±21.43）U/L, DBil（231.65±20.78）μmol/L, and TBil（392.52±25.64）μmol/L in the secondary infection group at the time of diagnosis were significantly higher than those in the non-infected group（P＜0.001）. CONCLUSION Secondary infection of liver failure aggravated liver burden, further damaged liver function, and accelerated the progression of liver failure, with serum procalcitonin and anti-inflammatory factors increased, proinflammatory factor levels decreased and immune function indicators decreased, which had certain reference value for the diagnosis, treatment and prognosis of secondary infection of liver failure.