Abstract: In order to investigate the distribution of copper particles in poly-4-methyl-1-pentene (PMP) low density foams, the high resolution X-ray computer tomography was used to scan PMP/Cu samples and the CCD camera to record the images. After image processing and 3D reconstruction, 3D spatial distribution of the copper particles in PMP/Cu foams was obtained. 3D visualization shows that copper particles are aggregated in the PMP foams, copper particle aggregates with different sizes have distinctly different morphologies, that is, small aggregates tend to be spherical while big aggregates are relatively longer and like a short stick, which agrees well with the results obtained by high resolution electron microscopy. The research results show that the high resolution X-ray computer tomography can be used to observe the high Z metal particles doped in low density porous materials without destructing the samples.