This article aims to develop a stress sensing technique using both subsurface longitudinal (SSL) waves and 1-3 composite transducer for a pressurized tank. Time-of-flight (TOF) of an SSL wave is affected by the elastic modulus of the structure, which is influenced by internal pressure. Therefore, it can be presumed that TOF variation of the propagated wave is correlated to the tank’s internal pressure and structural stress. This sensing mechanism has been commonly utilized in both stress and pressure measurement, yet the excitation signal and the transducer material have not been thoroughly investigated. For high signal sensitivity and accurate estimation of TOF, we employed 1-3 composite transducers as both ultrasound transmitter and receiver. In this study, the center frequency of the 1-3 composite is chosen to be 4.4 MHz so that the wavelength is shorter than the tank thickness. Next, for the purposes of generating the critical refraction angle (42?) and providing an acoustic impedance matching layer, brass wedges are employed as intermediate material between the active element and the tank structure. Finally, the performance of the sensing system is validated through a numerical simulation and experimental results. Simulation result verifies that the signal intensity becomes as much as 72.3 % greater than that of a single-phase thickness-mode transducer. Experimental results successfully exhibit that the time-delay of SSL wave is linearly proportional to the structural stress of the pressurized tank.