Geochemistry, Sr-Nd isotopic compositions of the volcanic rocks have been studied in this paper. The samples collected from Silurian Gongpoquan Group mainly belong to tholeiite series, except Dongqiyishan samples which belong to calcalkaline series. The volcanic rocks are chatacterized by enrichment in LREE and LILE (K，Rb and Ba)，and have negative anomaly in Nb, Ta, Ti (especially Yihatuoli), which suggest a characteristic of volcanic rocks related to subduction. PositiveεNd（t）and lower （87Sr/86Sr）tvalues（0.70340~0.70519）suggest that both fluidsediments and silicate melts derived from subducted oceanic slab are involved in the genesis of volcanic rocks in Gongpoquan Group. The tectonic settings of volcanic rocks collected from Yihatuoli are different from that of the central Beishan in Gansu, the former were formed in island arc setting and the latter were formed in the setting of a continental marginal arc.