Abstract: The laser ultrasound signal in nano AlP/SiO2 is collected with Laser-PVDF experimental system.Making use of the functions of multi-scale decomposing,reconstructing and de-noising of wavelet transform,laser ultrasound signal in nano AlP/SiO2 is processed.The direct longitudinal wave and its reflected echo are extracted,and the sound velocity of nano AlP/SiO2 is measured.The results show that Wavelet Transform is an effective processing method for complex laser ultrasound signal.