To investigate the risk factors for pulmonary fibrosis in patients with paraquat (PQ) poisoning. A total of 120 patients with PQ poisoning who were admitted from January 2012 to December 2014 were enrolled. According to the presence or absence of pulmonary fibrosis, the patients were divided into non-pulmonary fibrosis group (67 patients) and pulmonary fibrosis group (53 patients) . The Acute Physiology and Chronic Health Evaluation II (APACHE II) score was obtained on days 1 and 3 of poisoning. Routine blood test results, blood biochemical parameters, and radiological parameters were recorded, and the patients with PQ poisoning were followed up for survival and pulmonary fibrosis. A total of 39 patients with PQ poisoning died, resulting in a mortality rate of 32.5%. There were 53 patients who developed pulmonary interstitial fibrosis, yielding an incidence rate of 44.2%. Compared with the non-pulmonary fibrosis group, the pulmonary fibrosis group had a significantly higher age, a significantly higher dose of PQ, and significantly higher APACHE II scores on days 1 and 3 of poisoning (<0.01) , as well as significantly higher white blood cell (WBC) count and neutrophil count on day 1, significantly higher levels of urea nitrogen, creatinine, and blood glucose on days 1 and 3, and significantly higher activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (<0.01) . The logistic regression analysis showed that the dose of PQ, WBC count and neutrophil count on day 1, APACHE II scores on days 1 and 3 of poisoning, levels of urea nitrogen, creatinine, and blood glucose, and activities of AST and ALT were associated with the development of pulmonary fibrosis in patients with PQ poisoning. Oral dose of PQ, APACHE II scores on days 1 and 3 of poisoning, levels of urea nitrogen, creatinine, and blood glucose, activities of AST and ALT, and WBC count and neutrophil count on day 1 are risk factors for pulmonary fibrosis in patients with paraquat poisoning.