使用70%和90%能量持时定义，计算了汶川MS8.0大地震中获取的来自109个台站强震动加速度记录的相对持时，并以此在竖向及两个水平向上分别进行了回归统计分析，得到了地震动持时的空间变化关系,给出了适合汶川地震地震动的持时定义．对比分析了上盘和下盘2个区域持时空间变化特征，进一步计算了地震动竖向持时与两个水平向持时的比值，揭示出汶川地震地震动持时的空间变化特性．

Relative durations of strong ground motions from 109 station records of MS8.0 Wenchuan earthquake are calculated based on 70% and 90% energy duration definition. Attenuation relationships of the durations under different definitions are statistically analyzed for three component records and 90% duration definition is recommended. The relationships in the hanging wall and footwall of earthquake faults are compared and the ratios of vertical duration to horizontal duration are discussed for different areas.