中强地震孕育过程中，震中周边一定区域内的小震活动会因次级破裂的非均匀性而导致在各震级档的比例分配失调，从而采用古登堡公式拟合时的拟合优度会下降。利用这个规律，对玉树地震前一定区域内的地震运用地震拟合优度进行计算分析，结果表明，在玉树地震前一段时间，震中周边一定区域和青海省及邻区的地震拟合优度均表现出明显的下降异常。这一方法可以为如玉树地区这样地震监测能力较弱地区的中期预报提供参考性依据，弥补前兆台网分布稀疏的不足。

In the process of moderately strong earthquakes preparation, the magnitudes of small earthquakes activity near the epicenters  may anomalies because of heterogeneous fractures, and the optimization mimesis may be dropped which is calculated by Gutenberg relation. The optimization mimesis of Yushu Ms 7.1 earthquake is calculated, and the results show that the calculation presented the obvious descending anomalies in neighboring the epicenter before the event. And this may provide the reference for earthquake prediction in Yushu area.