Abstarct: A thick sequence of Late Cretaceous volcanic-sedimentary rocks of southwest of Sabzevar is located on the northern edge of Central Iran. This sequence includes the extrusive rocks such as basalt, trachyandesite, dacite and rhyolite, sub-volcanic intrusive masses with compositions of gabbro, gabbrodiorite, diorite and granite and volcanoclastic rocks (including tuff types). The Volcanic rocks mainly have porphyry, glomerulophorphy and sieve textures. Quartz, Plagioclase and Clinopyroxene are the main minerals forming volcanic rocks that are located in the microcrystalline matrix of these minerals. Plagioclase and Clinopyroxene are the main minerals forming gabbrodiorites and gabbro, and accessory and secondary minerals can be referred to amphibole, apatite, opaque, chlorite and sericite minerals. The texture of these rocks are granular and porphyry in the margin. Mineralogical diorite has plagioclase and amphibole as main minerals. Granites often have a medium to coarse-grain texture and they widely show graphical texture. Plagioclase, quartz and alkali feldspar are the main minerals of the granite rocks. Tuffs, quartz and plagioclase are main minerals forming in the area. Amphibole also observed in these rocks. Mineral chemistry and whole rock studies of the igneous rocks in the southwest of Sabzevar indicate the calk-alkaline to tholeiitic nature of the island arc. Liners trends for major, minor and trace element against SiO2 and these chemicals variations indicate the importance of fractional crystallization in the magmatic evolution. Chondrite- normalized spider of samples has an almost flat pattern of REE with negative Eu abnormalities in the granite samples. Primitive mantle-normalized spider diagrams the samples show enriched in elements such as K, Pb, U and Ba, and depleted in Nb, Ti, Ta, Th and Zr. Correlation between Geochemical data in Spider diagrams of the intrusive and extrusive samples of the southwestern of Sabzevar supports this hypostasis that the magma has been originated from mantel source in subduction setting. The normalized and spider diagrams show that the intrusive and extrusive igneous rocks of the southwest of Sabzevar have a significant geochemical consistency, and their magma is originated from the same mantle source in a subduction environment. In addition to existence the index fossils from the Late Cretaceous (Globutroncanna) in the region's pelagic limestone, which indicates the Late Cretaceous age for them, zircon U –Pb dating on the zircon of igneous rocks of southwest of Sabzevar give magmatic ages of 75-101 Ma (Late Cretaceous) for these rocks. Isotopically, the initial 87Sr/86Sr ratios of the extrusive rocks (dacite, rhyolite and trachyandesite) and intrusive (gabbrodiorite, diorite and granite) rocks are variable between 0.695 to 0.7061 and 0.7042 to 0.7052, respectively. The initial ratio of 143Nd / 144Nd in the extrusive igneous rocks of studied area is between 0.51293- 0.51301 and in the intrusive igneous rocks is between 0.51292- 0.51297. In general, the extrusive and intrusive igneous rocks have the same isotopic Sr and Nd values, which indicate their genetic relationship. The εNd value for the extrusive and intrusive rocks varies from 5.81 to 7.22 and from 5.91 to 7.38, which in terms of composition indicates the depleted mantle as the source of origin for the parental magma. The geochemical evidence suggests that generation the forming magma of the igneous rocks of southwest of Sabzevar from Sabzevar supra-subduction depleted mantle wedge in subduction island arc environment, during the subduction of the Neo- Thyan basin of Sabzevar during the Late Cretaceous, is subduction.