The objective of this research is to make the quality evaluation of tunnel lining by using infrared thermography. In-site studies are carried out at the Kaohsiung Hiziwan tunnel and the Daguan mountain tunnel to evaluate the quality of tunnel lining. The results of the studies show that the size, length, and scope of tunnel lining crack can be identify by infrared thermography images. If the temperature difference between normal and damaged tunnel lining is more than 3℃, the thermography image is clear.