According to the point of view that the transmissive hologram can be reconstructed by reflection, the analyses of transmission imaging and reflection imaging are both presented. We postulated a model of lens-mirror composition for the ±1 order images of a holcgraphie lens. By using the method of Fourier optics, authors obtained the expressions for the point spread function and the transfer function of a holographic lens with arbitrary aperture. From this the limited resolution and the cut-off frequency may be derived. The iahomogeneity of the colour blur of image is also discussed.