The reflection and transmission coefficient equations in multilayer bonded structures have been achieved by improved global matrix algorithm. The change of bonded strength have been simulated by the change of shear velocity in bonded layer.The curve between reflection coefficient and angle of incidence in immersion and plane ultrasonic longitudinal wave have been calculated in different bonding strength and the same frequency. The emulational graph had been compared and analyzed. The quantitative test of bonding strength and orientation of poor bonded district have been implemented. The conclusion can provide theoretic guidance for experimental research of bonded strength.