地震预警作为一种能够有效减轻地震灾害的手段已经被世界上越来越多的国家和地区所研究，并在实际应用中取得了显著的减灾实效。利用汶川主震及其余震的强震观测记录研究了特征周期τ_c与震级的相关性、位移幅值Pd与峰值速度PGV的相关性以及τ_c和Pd的乘积与震级的关系。使用的数据集时间跨度从2008年5月12日至2008年10月1日，遵从一定的挑选原则挑选出了共计54次震级大于等于4级的地震事件，包括主震、最大余震和4次大于等于6级的事件。统计结果表明，τ_c与震级以及Pd与PGV之间都有较好的相关性，验证了前人的统计结果。另外，τ_c和Pd的乘积与震级的关系也与台湾地区的结果一致。最后，研究结果被应用到了两款不同的仪器中，形成了一套现地地震预警系统。

As one of the effective ways to mitigate earthquake hazards, earthquake early warning (EEW) has been studied by many countries and regions in the world. They have achieved significant mitigation practical effectiveness during operations. We studied the correlation between the characteristic period τ_c and the event magnitude, between the peak displacement (Pd) and the peak ground velocity (PGV), and the relationship between the product of τ_c and Pd and the event magnitude. The used dataset spans from 12 May 2008 to 1 October 2008 and includes 54 events with magnitude greater than or equal to 4, among them the main event, the main aftershocks and 4 events with magnitude greater than 6. The statistical results show that there are good correlations between τ_c and magnitude, and between Pd and PGV, confirming previous results. In addition, the relationship between the product of τ_c and Pd and magnitude is similar to the result of Taiwan. Finally, the results are applied to two different instruments and an on-site early warning system is formed.