In this study, synthesis and characterize investigation of barium hexaferrite doped with ions of cobalt, chromium and tin with the formula of BaCo_xCr_xSn_xFe_12-3xO₁₉ was performed via mechanochemical method. For this purpose two samples were prepared with x values of 0.3 and 0.5. Phase and structural investigation by X-ray diffraction (XRD) and infrared spectroscopy (FT-IR) respectively,confirm the formation of barium hexaferriteswith minor amounts of hematite as secondary phaseafter heat treatment for 5 h attemperature of 1000 °C.Also, according to scanning electron microscope images (SEM) morphology of particles was perfectly hexagonal with an average particle size 600-650 nm.Based on magnetic parameters measured by vibrating sample Magnetometer (VSM) based on the value of coercivity, both samples were magnetically semi-hardand the highest saturation magnetization was obtained for the sample with composition of BaCo_0.3Cr_0.3Sn_0.3Fe_11.1O₁₉.The values of saturation magnetization (M_s) and the coercivity (H_c) were measured for this compound, 42.21 emu/g and 656 Oe respectively.Doped barium hexaferrite electromagnetic parameters was evaluated using a vector network analyzer (VNA) in the frequency range of 8-12.5 GHz.According to the results the maximum absorption was related to BaCo_0.5Cr_0.5Sn_0.5Fe_10.5O₁₉/resin epoxy composite with thickness of 5 mm at the frequency of 12.2GHzwas-15 dB.