Objective To investigate the changes in ATPase activity of diaphragm in rats with acute organophosphorus poisoning (AOPP) and to explore the effect of Xuebijing injection on the ATPase activity. Methods 24 clean healthy Spraue-Dawley(SD)rats were divided into control group,model group and Xuebijing treatment group by means of random number table,with 8 rats in each group. AOPP model was established by intra-gastrical administration of 50 mg/kg oxide dimethoate. In Xuebijing treatment group,after oxide dimethoate administration,intraperitoneal injection of Xuebijing(10 mL/kg)was given at the same time,while in control group and model group,equal amount of normal saline(NS)was injected via the same route. The rats were sacrificed at 6 hours after model formation,and their diaphragms were taken sterilely. The activities of Na+-K+-ATPase and Ca2+-ATPsae of diaphragms were detected by enzyme linked immunosorbent assay(ELISA). The histopathological changes in diaphragms of rats were observed with light microscopy. Results 6 hours after intoxication,the diaphragm Na+-K+-ATPase activity of rats in model group was markedly lower than that in control group(mmol?h-1?g-1:5.22±0.74 vs. 9.98±0.37,P<0.01),while the Na+-K+-ATPase activity in Xuebijing treatment group(6.93±1.14) was markedly higher than that in model group(P<0.05). The diaphragm Ca2+-ATPase activity of rats in model group was markedly lower than that in control group(mmol?h-1?g-1:7.45±0.74 vs. 12.08±0.74,P<0.01),while the Ca2+-ATPase activity in Xuebijing treatment group(9.35±1.67)was obviously higher than that in model group(P<0.05)after intoxication for 6 hours. Light microscope observation indicated that there were swelling and necrosis in diaphragm in model group,while in Xuebijing treatment group no necrosis was found. Conclusion The diaphragm was degenerated and necrotic in AOPP rats,Xuebijing injection can lessen the injury in such rats,and the curative effect may be related to the improvement of the Na+-K+-ATPase and Ca2+-ATPsae activities of diaphragm.