Abstarct: In recent years magnetic nanowires according to their applications in the field of magnetic storages with high-density and their giant magnetic resonance (GMR) has been of interest to many scientists and researchers. So far physical properties of different magnetic nanowires such as single-element nanowires and alloy nanowires have been investigated. Due to some favorable effects of non-magnetic elements on magnetic properties of nanowires, in this work synthesis of CoSn nanowires and their magnetic and structural properties were investigeted. In order to prepare our samples, first an alumina template was prepared by the multi-stage anodized method and then CoSn alloys nanowires with different concentrations of electrolytes in alumina template were synthesized by electrodeposition method. The concenteration of the elements in nanowires were measured by X-ray fluorescence spectroscopy (XRF). Magnetic and structural properties of nanowires were investigated by vibrating sample magnetometer (VSM) and X-ray diffraction (XRD) measurments respectively. Morever morphology of the samples were investigated by scanning electron microscopy (SEM). All these measurments were done on as-grown and annealed samples. Our results indicated that decreasing of Co and increasing of Sn concentrations in electrolyte solution were cause decreasing of Co and increasing of Sn atomic percents in nanowires. XRD measurments were indicated that with increasing of Sn atomic percent the crystalline structure changes from hexagonal to amorphous. The results of magnetic investigation of the nanowire showed that saturation magnetization and coercivity decreased as Sn concenteration in electrolyte increased. Annealed threatments in 500 ℃ at 30 minute in presence of Ar gas were changed magnetic properties of nanowires. For these samples coercivity and squareness signifacntly increased.