Abstract: The propagation characteristic of ultrasonic in the solid substrate and the filler droplet was investigated by using finite element simulation and experimental test.The results show that the ultrasonic vibration of the substrate surface is non-uniform.The ultrasonic vibration amplitude along the spreading direction first increases,and subsequently decreases before a final increase.The space of each peak amplitude location is approximately 10 mm.As the input ultrasonic vibration increases,the particle displacement of the substrate surface increases and is larger than that of the input value.The displacement field remains unchanged and the particle vibrates at a frequency similar to that of the input load.The acoustic pressure in the filler droplet increases with the displacement of substrate surface,which reaches ten thousands of pascals when the input ultrasonic load is higher than 7.5 μm.The finite element simulation results are consistent well with the experimental observations.