Abstract: Due to the high accuracy of the detector position in receiving system of satellite optical communication, the method expanding the focal depth was put forward to reduce the acquirement of the axial detector position accuracy. According to the central obstacle caused by receiving optical antenna, apodized annular-aperture logarithmic axicon was utilized to achieve uniform distribution of the beam on the optical axis. By means of the geometrical law of energy conservation, the phase distribution function and the intensity transmittance function of the diffractive axicon were obtained. Numerical simulation results show that the capacity which uses apodized annular-aperture logarithmic axicon to achieve uniform distribution of the beam on the optical axis is much larger than that of ordinary lenses', which can enhance the reliability of the acquisition, tracking and communication in satellite optical communication system significantly.