When a satellite photoelectric imaging system is carried out on detection and recognition for space point target imaging, the point target will produce the phenomena of dispersion and striation because of the influence of diffraction and aberration of the system and the relative motion between the system and the target. A mathematical model of target imaging dispersion is derived based on the visible light reflectance characteristic of space target and the point spread theory of system, and the effect of diffraction and aberration on dispersion characteristic of the target imaging are analyzed and simulated; the relative motion relationship between the system and the target is analyzed. Expression for the striation length on image plane of the target is deduced within single frame integration time, and the influence of orbit altitude and observation angle on the striation is studied. Results show that the aberration makes dispersity increase and intensity of image patch decrease; striation length increases with the target′ s orbit altitude reducing and observation angle increasing under the condition of certain parameters and orbit altitude of imaging system.