This paper presents a theoretical and experimental investigation of the non-contact detection of composite laminates by using laser ultrasonics, with the purpose of promoting the application of advanced laser ultrasonic testing technique in aviation industry. Typical aeronautical composite laminates with artificial defects are prepared as specimens. Theoretical models concerning the interaction of pulse laser and composite laminates are built to calculate and analyze the characterization of the internal defects with laser ultrasonics, and the theoretical results are verified by experiments. A fully functional laboratory prototype of laser ultrasonic testing system for composite laminates is developed, and the effective detection is realized. The research achievements provide technical support for the industrial application of laser ultrasonic testing technique in the manufacturing quality control of aeronautical composite structures.