College of Earth Sciences，Jilin University，Changchun 130061，China

The petrology and petrography of Jianshan volcanic mecganism in Xingcheng，Liaoning have been analyzed，and the geochemistry of hornblende andesites were studied． The results show that the hornblende andes- ites are characterized by SiO 2 =58. 42% ～60. 42%，MgO =1. 39% ～3. 08%，Mg # =31 ～50，Al 2 O 3 =16. 17% ～17. 5%， Sr = (387 ～1 325) ×10^－6 ，Yb = (1. 15 ～1. 57) ×10^－6 ，Y = (12. 1 ～16. 8) ×10^－6 ， respec- tively． In addition，the volcanic rocks are enrichment in LREE and LILE and depletion in HREE，with high Sr and Sr/ Y values and low Y and Yb values，showing the geochemical characteristics of adakite． However，they are low in Mg#，indicating the volcanic rocks may originate by partial melting of the thickened mafic lower crust，and could be related to the subduction of the Paleo- Pacific Plate beneath the Eurasian continent．