分析2013年云南洱源5.5级地震前地震活动异常，发现震前震中附近长达8个月M≥3.0地震平静，云南地区2013年2月4级地震连发，在震前一个半月内快速形成M≥3.0地震条带，地震当天在震中东北方、距离约30km处发生前震序列。结果表明，洱源地震的孕育、发生与大区域应力活动有关。

Analyzed the seismicity anomalies before the Eryuan earthquake, It is found that M≥3.0 earthquakes near by the epicenter are quiet as long as eight months and M4.0-4.9 earthquakes occurred one after another in February in Yunnan region before the Eryuan earthquake, besides, a earthquake belt of M≥3.0 formed in one and a half months before the Eryuan earthquake. At the same day, the foreshock sequence that occurred in the northeast of epicenter, about 30 kilometers away is an important seismicity anomaly before the Eryuan earthquake. It is revealed that the gestation and occurrence of Eryuan earthquake are related to the stress activity in large area.