Abstract:TbDyFe alloy can be used in high frequency and even ultrasonic frequency devices. The hysteresis and loss of TbDyFe alloy (TerfenolD) are serious under high frequency magnetic field (f>1 kHz). It is very important to study the dynamic magnetic properties and loss properties of the TbDyFe alloy laminates with different thicknesses for designing the devices in high frequency range. The AMH1MS dynamic magnetic property testing system was used to measure the dynamic hysteresis loops of TbDyFe alloy laminates with different thicknesses under different driving magnetic field frequencies and magnetic density amplitudes. Based on the dynamic magnetic theory and loss calculation model, the dynamic magnetic property parameters of TbDyFe alloy laminates with different thicknesses were compared and analyzed, and the loss mechanism in high frequency range was deeply studied. The experiment results show that when the magnetic density amplitude Bm is 005 T and the frequency is 5 kHz, compared with that of a single 2 mm thickness sample, the dynamic hysteresis loop of the 1 mm thickness laminate sample becomes narrower laterally, the required magnetic field strength is reduced, the coercive force and magnetic energy loss values are reduced by 264% and 281%, respectively, and the amplitude permeability is increased by 117%. Under certain magnetic density magnitude, the value of the real part and imaginary part of the complex permeability, as well as the amplitude permeability of TbDyFe alloy present a tendency of data decreasing and speed slow down as the frequency increases. At the condition of high frequency and high magnetic density (f>5 kHz, Bm>006 T), the thickness decreasing makes the loss decreasing of TbDyFe alloy more obviously.