In this paper,a single-frequency two-dimensional(2-D)holographic image reconstruction technique is presented for the target in a slant plane under the illumination of terahertz(THz)Gaussian beam.Analytical expression of the reconstructed 2-D point-spread function is derived.The quantitative relationship between the spatial resolution and the parameter of the transmitted Gaussian beam is obtained and subsequently proved with simulated data.The image reconstruction technique is then investigated for the target in a curved surface which can be applied in a practical THz holographic imager for personnel screening.Finally,some simulation and experiment results are given in details to prove the techniques and demonstrate their potential application for personnel screening.