Objective To investigate the therapeutic effects of recombinant human erythropoietin(rhEPO)on brain mitochondrial energy metabolism and mitachondrial respiratory functionin after brain injury in rats.Method A total of 63 Sprague-Dawley rats were divided randomly into three groups:the rhEPO treated group(n =28),the control group(n=28),the shanl group(n=7).The models of contusion of brain caused by freefalling were set up in rhEPO treated group(n=28).The recombinant human erythropoietin was intraperitoneally injected in dose of 10 U/g immediately after brain injury and it was repeated every 10 hours in rhEPO group treated.The same models of contused brain were made without rhEPO treatment as control group(n=28).In control group,the same volume of normal saline was used in replacemem of rhEPO.Aburr hole was made on the skull of the sham group(n=7),but the brain tissue was not wounded.The mitochondria were isolated at 6 h,12 h,24h,48 h after trealment,respectively.The activity of ATPase and SOD,the content MDA and brain mitochondrial respiratory function were measured by biochemical technique.The data were analyzed with the F-test and t-test.Results The activity of ATPase(P＜0.05),SOD(P＜0.01)and brain mitochondrial respiratory function(P ＜0.05)were increased.and the levd of MDA in brain mitochondria was reduced markedly in rats treated with rhEPO.Conclusions Treatment with rhEPO can alleviates the secondary brain injury by affecting mitochondrial function.