As an important part of Carboniferous volcanic rocks in eastern Tianshan Mountains, the volcanic rocks of the Dikan'er Formation have great constraints on the tectonic evolution of the Juoluotage belt. These volcanic rocks are bounded by the southern margin of Tu-Ha basin in the north and the Shaquanzi fault in the south. The major and trace elements and Sr-Nd isotopes of the volcanic rocks are discussed in this paper to constrain the petrogenesis and tectonic settings. The volcanic rocks are composed of calc-alkali basalt, andesite and rhyodacite assemblages, which are products of partial melting of garnet-spinel lherzolite mantle. The primary magma has experienced crystallization differentiation of olivine and clinopyroxene for basalt, and that of plagioclase and magnetite for andesite and rhyodacite. They are relatively enriched in large-ion-lithophile elements and light rare-earth elements, and are depleted in high-field-strength elements. The patterns of trace elements of basalt are similar to those of arc basalt, while the trace element patterns of intermediate-acid rocks are similar to those of the upper crust. Neodymium isotopic characteristics [εNd(t)=-0.14～5.69] and trace element patterns of the volcanic rocks indicate derivation from a moderately depleted mantle source which was metasomatized by subduction-related fluid and involvement of minor crustal contamination. The trace element patterns of basalt and the plots for tectonic setting suggest that the volcanic rocks were probably formed in a back-arc basin environment.