Abstract: A series of magnetic FeB nano-films with the same thickness were prepared by DC sputtered method.Different sputtering powers were used to attain nano-films with different magnetic properties.The prepared nano-films were studied using vibrating sample magnetometer（VSM） and FMR.As the sputtering power increases,the saturation magnetization（4πM_s） and magnetic loss（μ″） increase,while the coercive force（H_c）decreases,which is attributed to the appearance of nanocrystalline α-Fe.The phenomena can also be proved by FMR experimental results.