Electromagnetic ultrasonic transducer can be used for non-contact detection, which is convenient to use, but its disadvantage is low efficiency of energy exchange.To increase the energy conversion efficiency of electromagnetic ultrasonic transducer, The paper analyzed the working principle of electromagnetic ultrasonic transducer.it also modeled and simulated the electromagnetic ultrasonic transducer by using COMSOL Multiphysics. And the influence of different placement modes and geometric size of the permanent magnet on the excitation Lorentz force of the transducer was analyzed. By orthogonal experiment , the geometric parameters of the butterfly coil are optimized to obtain the best efficiency of shear wave energy transfer, Finally, The thickness test of aluminum plate was carried out by using ultrasonic detection system. The results show that the shear wave excitation efficiency is higher when the permanent magnet is placed vertically, and the amplitude of the ultrasonic shear wave excited by the butterfly coil is 50% higher than that by the spiral coil.T he butterfly coil has better shear wave energy transfer efficiency than the spiral coil.