Micro-CT is a new three dimensional imaging tool based on x-ray imaging mechanism and with ultrahigh spatial resolution. It can be used to image all kinds of samples or live small animalsunder non-destructive condition. In this paper, a micro-CT prototype system with high spatial resolution was developed. From the projective images and reconstructed cross-sectional images of a small insect sample, the phase-contrast effect with the edge-enhancement trait can be observed clearly. The cross-sectional images also show that the developed micro-CT system has the detail detectability down to 12 micrometers.