Abstract：The changing rule for infrared thermal image boding of the rock with crack is essential for the geotechnical engineering，especially for the underground engineering. In order to study the rule，infrared thermal images for the failure process of rock with fracture are carried out. The size of the rock sample is 20 cm×10 cm×2 cm with a crack of 45°to the horizontal direction at the center and with the length of 2 cm. Considering the fact that sample will effect the results of the observation for infrared thermal image during the experiment，the laminated granite sample is used to replace the cylinder or cuboid sample. The achieved results under uniaxial compression indicate that intensity of the microruptures has close relation with the thermal effects. When the main fractures happen，there is a strip of high temperature that will appear at the destructive local area. During loading process，the abnormality of infrared temperature has three kinds of behaviors as follows：(1) temperature falls first and rises just before fracture；(2) temperature rises and falls alternately，and rises before the fracture；and (3) temperature rises slowly at first，and then rises quickly before the fracture appears. Even for the same rock sample，the behaviors of the infrared phenomenon may be different during failure process.
