In this work, based on the use of high frequency (20MHz) focus ultrasonic transducer and echography, a high-resolution three-dimensional acoustical imaging technique has been developed, permitting 3D reconstruction of the internal structure of materials at mesoscopic level. The data acquisition is realized by the combination of A, B and C scan in reflection mode. The 3D material structure is obtained by applying a surface reconstruction algorithm to the scanned volumetric data. Two application examples are shown to valid the method: the imaging of a 2D textile composite sample before and after a mechanical impact testing, and a porous bone sample. The material structure can be quantitatively evaluated and analyzed.