Objective To summarize clinical feature and prognosis of patients with acute paraquat (PQ) poisoning and analyze the predictive performance of NLR (Neutrophil-to-Lymphocyte Ratio), PLR (Platelet-to-Lymphocyte Ratio), LMR (Lymphocyte to Monocyte Ratio), WLR (Platelet-to-Lymphocyte Ratio), SIRI (System Inflammation Response Index) and SII (Systemic Immune Inflammation Index) for in hospital death. ,Methods General information, laboratory examination and prognosis of acute PQ poisoning patients were retrospectively collected and analyzed from whom admitted to emergency department of West China Hospital from September 1, 2010 to January 31, 2022. Patients with acute PQ poisoning were divided into survival group or non-survival group according to their in-hospital outcome. The risk factors of death in hospital were screened by receiver operating characteristic curve (ROC). Results A total of 452 patients with acute PQ poisoning were enrolled, of which 207 (45.80%) were males, with an average age of 30 (22.75, 43.00）. 180 patients died in hospital. Compared with the survival group, the levels of age, NLR, WLR, SIRI at admission in the non-survival group were significantly increased (P<0.05). The ROC showed that the area under the curve (AUC) of SIRI, LMR, WLR, NLR and SII were 73.29%,63.16%,59.92%,59.81% and 58.84%, which were greater than that of qSOFA score (56.07%, P＜0.05). Subgroup analysis shows that SIRI has more remarkable relationship with the mortality of PQ poisoning in patients whose age were 14-17 years or the duration of illness ranged from 6 hours to 11 hours (AUC<18years =86.25%, AUC6-11 h=84.13%).Conclusion SIRI can be used as a predictor related to in-hospital death in acute PQ poisoning patients. Among groups aged 14 to 17 or patients whose duration between onset of poisoning are ranged from 6 hours to 11 hours, SIRI has a significant value to assess and forecast their risk of in-hospital mortality