Abstract: Based on composition of chemical analyses of rocks in Padong Area,Sumatra (Indonesia) comparing with the data of the typical adakitic rocks,this paper discusses the geochemical characteristics and their significance of tectonic setting.The comparative results shows that the trace element composition of the adakite-like rocks have the characteristics of low Sr contents (general 3.88×10^-6~83.6×10^-6),low Y contents(≤20×10^-6),low Yb contents(≤1.9×10^-6)of HREE,and lower Sr/Y ratio (1.09~18.55).On the chondrite-normalized spider diagram of trace element,there are positive peak of Th,Ba and strongly negative anomaly of Nb、Ta、Ti elements.The La/Yb ratio of REE are within the range of 1.28~35.46,and there are two types of chondrite-nomalized rare earth elements pattern:enriched and no enriched model,belonging to C- and O-type adakite respectively.The tectonic setting of theses adakite-like rocks are located at the volcano-arc of active continental margin near ocean-continent collision zone.The igneous magma derived from the areas of partly melting of seduction ocean slab plus partly molting and assimilation o f mantle wedge(MASH).The distribution of adakite-like rocks in this area is in perfect accord with Cu-Au deposits of skarn type and iron deposits as well as hypothermal hot-spring Au zone.That meams the adakite-like rocks have a big significance in exploration.