Thermal fracture behavior of the 3D-woven SiC/SiC composites was evaluated by a direct diode laser (DDL) irradiation with shading method. The shading method generated a circular shade at the central portion of square sample during quick heating with the DDL. In order to assess microdamage due to thermal stress, the acoustic emission (AE) signals were monitored during the test. The surface temperature distribution was measured by using infrared cameras and then used as input to compute the stress distribution using FEM. It was shown that the surface temperature near the central portion was kept low while the temperature in the outer region of the sample remarkably increased and that the temperature distribution produced biaxial tensile stress field at the center of the sample. The AE activity was increased with increasing the temperature difference between the central and the outer region of sample. Microscopic observation confirmed that microdamage was accumulated on the specimen top surface where the AE signal with maximum amplitude was located.