The pattern of thermal excitation is one of the main factors which affect the detection reliability in infrared thermal wave nondestructive testing. The experiment is designed to establish the basic principle for selecting pattern of thermal excitation. In experiment, glass fiber reinforced laminate which embeds artificial defects is a tested object, and four patterns of thermal excitation are organized as follows: pulsed flash lamp, boiling-water bath, oven thermostatic heating, and pulsed ultrasound. The thermal stimulus-response signal which is the intensity of infrared radiation of specimen surface is acquired and processed. The influence of four heating ways on the testing results is analyzed and contrasted from three respects: signal to noise ratio of thermal imaging, curves of infrared radiation intensity, and degree of defect′s detectable, and a basic principle for selecting pattern of thermal excitation for fiber-reinforced composites is gotten. In order to improve the detection reliability, this principle should be followed when selecting thermal excitation pattern.