From August 2014 to November 2014,the Zhejiang Digital Seismic Network and reservoir monitoring network with high density,high resolution monitoring stations made complete records of Wenzhou Shanxi reservoir earthquake sequence of 3000 events with the maximum magnitude of M4.2. This paper discussed tectonic characteristics of the earthquake sequence in terms of the 3D epicenter location,focal mechanism solution and the geological characteristics in the reservoir area. The linear fitting of the HypoSAT positioning results a showed that the main shock occurred in the NW trending faults and the earthquake sequence along the active fault dense band has a strike of 305° with a SW tendency and 85° dip. By using P wave first motion focal mechanism of the earthquake symbols we obtain the average focal mechanism of M>3.5 earthquakes. The nodal plane B has a strike of 308° with an 84° dip. The field geological survey and research shows that the strike,dip and tendency of section B are consistent with the Shuangxi-Jiaoyang fault. The comprehensive analysis reveals that the Shuangxi-Jiaoyang fault in NW is the seismogenic structure of the earthquakes. Relationship between the earthquake and the earthquake fault and geological analysis in this paper results reflect the prediction has important theoretical value and practical significance in the study the earthquake seismogenic mechanism and future earthquake.