Abstract: Objective: To explore the significance of early measurement of plasma paraquat concentration in assessing the severity of kidney injury and predicting the outcome in patients with acute paraquat poisoning. Methods: According to the plasma paraquat concentration measured on admission, 55 patients with APP were divided into low concentration group (<0.5 μg/mL) in 15 cases, middle concentration group(0.5 to 2.0 μg/mL) in 15 cases, and 25 cases with high concentration(>2.0 μg/mL). The highest values of serum urea and creatinine levels were detected during hospitalization in these groups were compared, the mortality was also compared. Results: Serum creatinine and urea levels were significantly higher in high and middle concentration groups than those in low concentration group (P<0.01), while serum urea level in middle concentration group was significantly higher than that in high concentration group (P<0.01). The mortality was higher in high concentration group than in middle and low concentration groups(P<0.05 and P<0.01). Conclusions: Plasma paraquat concentration measured in the early stage of paraquat poisoning could be used to assess the severity of kidney injury and predict the outcome in patients with acute paraquat poisoning.