Objective To investigate risk factors and prognosis of hemorrhagic transformation(HT)in acute cerebral infarction patients treated by intravenous thrombolysis with recombinant tissue plasminogen activator(rt-PA).Methods All 128 patients with acute cerebral infarction were treated with intravenous rtPA within 6 hours from stroke onset.The clinic records and laboratory datas of pre-and post-treatment were statistically analyzed between HT group and non-HT group to find potential risk factors to HT and contributors of prognosis.Results HT occurred in 29 patients(22.66％),including 16 patients with symptomatic ICH(12.50％)and 2 patients died(6.90％ of HT).Logistic regression analysis showed that history of atrial fibrillation(OR =1.293,95％ CI 1.224-1.589,P =0.001),CT density changes with mass effect or edema(OR =2.452,95％ CI 1.132-3.309,P =0.034),diastolic blood pressure ≥ 100 mm Hg before thrombolytic therapy(1 mm Hg =0.133 kPa,OR =9.265,95％ CI 1.435-59.836,P =0.019),blood glucose ≥ 11.1 mmol/L(OR =3.037,95％ CI 0.252-57.593,P =0.047),NIHSS score ＞ 15 points (OR =8.752,95％ CI 1.035-30.285,P =0.023)and thrombolysis time ＞ 3 h(OR =98.74,95％ CI 5.067-186.120,P =0.002)are independent risk factors for HT; among these factors,baseline blood glucose(OR =3.265,95 ％ CI 0.435-59.863,P =0.045),NIHSS score(OR =10.453,95 ％ CI 5.647-38.185,P =0.003)and thrombolysis time(OR =2.541,95％ CI 1.098-51.086,P =0.017)also are prediction factors of the prognosis of HT.Conclusion Risk factors associated with HT are diastolic blood pressure before thrombolysis,glucose level,degree of neurological deficits,CT early changes,atrial fibrillation and thrombolytic time.Glucose level,neurological deficits and thrombolysis time affects the prognosis of patients.