The triamino trinitrobenzene(TATB)granule deformation and structural evolution during compaction process were studied by x-ray tomography technology and deformation characteristics of deformable material. The CT images show that the deformation orientations of granules in the central part are mostly downwards. In the meanwhile, there are arching between the granules near the edge of mould. The porosity changing mainly happens in the initial stage of compaction with the forming pressures of 0 MPa to 10 MPa, and the porosity of each part(5, 20, 35 mm away from the top surface) decreases 73%, 62% and 58%, respectively. During each compaction process, the porosity increases from the top down and the displacements mainly take place along the axial direction. Friction between the mould and granule is greater than that between the granules, which makes the displacements of the granules in the central part larger than granules at other parts. Results show that X-ray tomography can nondestructively characterize inner structural evolution of TATB granules during compaction. Morphology changes and contact relations of granules reveal the interaction mode between the granules. The displacements of granules indirectly reflect the internal stress transfer in the explosive.