Abstarct: Cenozoic alkaline volcanic belt of Abbas abad is located in South of Sabzevar ophiolitic belt and in Northeast side of Central Iran structural zone. The volcanic and volcano – sedimentary rocks of this region, are composed of an alternation of basic – intermediate volcanic rocks and related pyroclastics which associated with interbedded sedimentary rocks (tuffaceous shale, tuffaceous sandstone, shale, siltstone, sandstone, conglomerate and Nummulitic limestone). Field and laboratory studies indicate that alkaline basaltic – thrachyandesitic lavas erupted into a very shallow to shallow open sea in the middle – late Eocene. The studied volcanic rocks have a lithological range include olivine basalt, trachybasalt, basaltic trachyandesite and trachyandesite, that show a fractionation trend of olivine basalt to trachyandesite. Petrographic evidences indicate continuous changes have been done during evolution of in these rocks evolved during, some of them are as follows: appearance and disappearance of some mineral phases and textural disequilibrium (such as reaction rims, inclusion, sieve texture and zoning in plagioclase and clinopyroxen). Geochemical characteristics indicate that the studied rocks have sodic alkaline nature and evolved by fractional crystallization and with less important magma contamination. Positive anomaly of LREE and LILE and negative anomaly of HREE found in these rocks. Negative anomalies of HFSE (e.g. Ti, Nb, Ta) in studied rocks is the indicator of their arc tectonic settings. Magma forming of Abbas abad volcanic rocks probably generated from low partial melting (14 – 16 percentage) of a garnet lehrzolitic source rocks in 80 to 100 km below the surface of the earth. It resulted from partial melting of Neotethyan subducted oceanic crust, beneath the Northern parts of Central Iran zone, and its overlaying mantle wedge in a arc subduction zone.