Abstract: The plasma spraying process was adopted to spray the turbine blade with NiCrAlY coating. ultrasonic infrared thermography technique was used to detect turbine blade before and after spraying and achieve two crack defect detection. The penetration detection technology can only detect one crack defect in the turbine blade before spraying and however cannot detect crack defects in the turbine blade after spraying. Finally, the turbine blade after spraying was dissected and detected by metallographic microscopy and two crack defects were found. It verified the effectiveness of ultrasonic infrared thermography for crack detection of turbine blade with coating layer. The comparison results show that ultrasonic infrared thermography can detect the crack defects in turbine blades before and after spraying.