Abstract: Objective : To evaluate the prognostic factors for patients with astrocytoma treated by postoperative radiotherapy. Methods : A total of 56 cases with pathological evidence were studied retrospectively, of which 35 underwent the subtotal resection, 21 had grossly total resection, 22 were grade Ⅰ～Ⅱand the other 34 were grade Ⅲ~Ⅳ. The operation radiotherapy interval was less than 30 days in 21 cases out of 56. Patients of all cases received the conventional fractionated irradiation with a 4~6MV high -energy x-ray. The whole brain irradiation with an absorbed dose of 30 to 35Gy was conducted,then the local boost with 20 to 30Gy. The dose for target area was 50 to 60 Gy. Part of the cases did not receive the whole brain irradiation but single port exposure only. Results : The five -year survival rate of the group was 41.1N, among which the prognosis for those with the low pathological grade ( Ⅰand Ⅱ), an age below 50 and a longer interval (30 days and over after surgical operation) before postoperative radiotherapy would be better than the controls. There was a statistically significant difference for the survivals (P<0.05). Conclusion : The patients’ age, pathological grade and the interval between operation and radiotherapy are the major prognostic factors.