In particular, CFRP (carbon fiber reinforced plastics) composite materials have found wide applicability because of their inherent design flexibility and improved material properties. CFRP composites were manufactured from uni-direction prepreg sheet in this paper. However, impacted composite structures have 50-75% less strength than undamaged structures. It is desirable to perform nondestructive evaluation to assess material properties and part defect in order to ensure product quality and structural integrity of CFRP. In this work, a CFRP composite material was nondestructively characterized and a pitch-catch technique was developed to measure impacteddamaged area using an automated-data acquisition system. Also one-sided mode was performed to scan defect both manual contact measurement and an immersion tank. It is found a pitch-catch signal was found to be more sensitive than normal incidence backwall echo of longitudinal wave to subtle flaw conditions in the composite, including fiber orientation, low level porosity, ply waviness, and cracks. The paper describes the depth of the sampling volume with the head-to-head miniature Rayleigh probes and also ultrasonic C-scan images are acquired experimentally using one-sided measurement and a conventional scanner.