Evaluations for biocompatibility and structural integrity of the tissue-engineered vessel wall before and after grafting it are important. These are closely related with mechanical properties. Therefore, in vitro and in vivo ultrasonic measurement systems for tissue-engineered vessel wall evaluation was developed based on the ultrasonic elasticity measurement method suited to the evaluation of mechanical properties, in this study. Based on the pressure - strain loops attained by the ultrasound catheter and pressure sensor, elastic modulus and compliance are measured. Feasibility studies for the measurement systems were conducted by using rubber tube phantoms and canine vein. Experimental results revealed that the developed systems could provide equivalent accuracies to standard tension test.