红外热成像技术是一种新型的无损检测技术，能够成功应用于各种类型材料缺陷检测，但随着无损检测要求的不断提高，特别是对于新型航空航天材料的缺陷检测，如微小尺度缺陷和疲劳损伤等，因此需要加强各种无损检测技术在检测微弱信号方面的能力。锁相热成像技术是一种高灵敏度的热成像技术，在此主要探讨了锁相热成像技术的原理、实现方法以及实验中注意的问题。

Thermography is considered as an efficient tool in detecting the defects of most kinds of materials. But with the higher requirements of NDT, especially for the aviation materials such as minuteness defects and fatigue, it becomes a challenge to every NDT methods. It has to enhance its ability in detecting the faintness heat sources. Lock-in thermography is a sensitive tool to overcome these difficulties. The basic principles, realization and key points of lock-in thermography were discussed.