A tomography device based on a conventional laboratory x ray source, polycapillary parallel x ray lens (PPXRL), and polycapillary collimating x ray lens (PCXRL) is designed. The PPXRL can collect the divergent x ray beam from the source and focus it into a quasi-parallel x ray beam with a divergence of 4.7 mrad. In the center of quasi-parallel x ray beam, there is a plateau region with an average gain in power density of 13.8 and a diameter of 630 μm. The contrast of the image can be improved from 28.9% to 56.0% after adding the PCXRL between the sample and the detector.