Abstract: Addressing the detection challenge of interface debonding in multilayer bonded structures of solid rocket motors, simulation analysis and experimental research were conducted by constructing dispersion equations combining layered equivalent models and transfer matrices. Based on Lamb wave dispersion curves and simulated detection echo signals, appropriate detection frequencies and incident angles were selected. Multilayer structure debonding specimens were fabricated, and testing was performed using an oblique incidence water immersion detection system. According to the dispersion curves, the detection frequency for interface Ⅱ debonding was determined to be 2 MHz, and for interface Ⅲ debonding, 1 MHz. Simulation calculations based on the determined detection frequencies and incident angles showed that for detecting the bonding condition of interface Ⅱ, only the second wave packet needed to be focused on; for interface Ⅲ, only the second wave packet needed to be focused on. Subsequently, debonding tests for interfaces Ⅱ and Ⅲ were conducted. The results showed that using a 2 MHz ultrasonic transducer at an 11° incident angle for interface Ⅱ and a 1 MHz ultrasonic transducer at a 10° incident angle for interface Ⅲ could detect debonding defects with dimensions (side length) of 50 mm × 50 mm.