Abstract: The lesser false vampire bat, Megaderma spasma has complicated pinna structure with which the bat receives the echolocation pulse. A comprehensive acoustic characterization of the spatial sensitivity of the tragus in the pinna from a lesser false vampire bat has been obtained with the means of numerical methods and visualization techniques. Hundreds of cross-section images of the pinna shape were acquired through a high-revolution x-ray microtomography. In order to clear away the glitches and noises, cross-section images were processed by an isotropic Gaussian smoothing kernel and binarization processing. The modified images were converted into another digital representation. This kind of digital representation was composed of cube voxels. The original and other modified pinna shapes of the lesser false vampire bat were obtained by manually handling these voxels. The first one was the original structure of the pinna in esser false vampire bat. Compared with the original structure, the second one had no tragus in pinna. Furthermore, setting up a finite-difference time-domain model of diffraction from which directivities were predicted by virtue of forward wave-field projections based on a Kirchhoff integral formulation. Digital shape manipulation was used to study the role of the tragus in detailed numerical experiments. We show that the tragus in the pinna authentically had an impact on the acoustic near-field sound pressure magnitude as well as the far-field directivity patterns. In the effects on the near-field sound pressure magnitude, the most significant differences between the present and absence of the pinna appeared at the frequency of 50 kHz and 70 kHz. With the absence of the tragus in the pinna, changes in the far-field directivity patterns are the number of side lobs decreased in the range of low frequencies and high frequencies, however it’s obvious to see some side lobs combine into a main lob in the intermediate frequency. In addition, the tragus in the pinna from the lesser false vampire bat expresses clear and definite frequency selectivity.