Computed tomography has been proven to be useful for non-destructive inspection of structures and materials.We build a three-dimensional imaging system with the photonically generated incoherent noise source and the Schottky barrier diode detector in the terahertz frequency band (90-140 GHz).Based on the computed tomography technique,the three-dimensional image of a ceramic sample is reconstructed successfully by stacking the slices at different heights.The imaging results not only indicate the ability of terahertz wave in the noninvasive sensing and non-destructive inspection applications,but also prove the effectiveness and superiority of the uni-traveling-carrier photodiode as a terahertz source in the imaging applications.