Abstract： Objective To investigate the variation of electrocardiogram (ECG) in the course of aneurysmal subarachnoid hemorrhage (SAH) for predicting the prognosis. Methods The in-hospital data of 108 cases with aneurysmal SAH who had underwent ECG re-examination were retrospectivelyanalyzed to find out the relationship between characters of ECG and prognosis. Results Of the 108 cases, aneurysm clamping by eraniotomy was performed in 41 and endovascular intervention in 67; a total of 89 cases (82.4%) presented abnormal ECG primitively, 62 patients had 2 kinds of ECG changes at least; 71 patients presented abnormal ST-T, 13 cases with abnormal cardiac rhythm, 14 cases with delayed Q-T intermediate stage, 37 cases with abnormal T wave, 9 cases with abnormal Q wave, and 7 cases with other changes; 99 cases recovered in ECG re-examination, 5 cases partly recovered and 4 cases aggravated. GOS score was 4-5 in 98 cases, 3 in 7 cases, and 1-2 in 3 cases. Conclusion Though the type of ECG variation has no significant correlation with SAIl prognosis, ECG monitoring during the course of SAH is of important value for predicting the prognosis.