The electromagnetic space of large-scale Low Earth Orbit(LEO) satellite constellation system is complex and difficult to observe. The link characteristics of LEO satellite constellation are studied. Firstly, taking Starlink and OneWeb constellations as the research objects, according to the constellation parameters of LEO satellites, Equivalent Isotropically Radiated Power(EIRP) values are obtained and visualized. Then the data of LEO electromagnetic satellite are analyzed to obtain the numerical relationship between attenuation characteristics and time, frequency, etc. The inter-satellite link interference and its temporal distribution characteristics are calculated. The characteristic values of relative interference time are obtained, as well as the attenuation and time-frequency multi-dimensional characteristics of inter-satellite data. The time characteristics of interference in different scenarios are analyzed. The inter-satellite link interference of large-scale LEO satellite constellation system is studied from multiple dimensions and verified by simulation. Finally, it is proved that there is interference in the inter-satellite links among large-scale LEO satellite constellation systems, and the higher the frequency is, the more obvious the interference is.