The mechanical property of sintered MoSi2 materials has been investigated, based on the detailed examination of their microstructures. The nondestructive technique by an ultrasonic wave was also used for evaluating the damage behaviors of MoSi2 materials suffered from the cyclic thermal shock. MoSi2 materials were sintered at the temperature of 1723 K. The flexural strength of MoSi2 materials gradually decreased with increasing the thermal shock cycle, accompanying the extensive creation of surface cracks. The increase of thermal shock cycles resulted in a great decrease of ultrasonic wave velocity and a linear increase of attenuation coefficient for MoSi2 materials.