Abstract: With the increasing of non-geostationary orbit satellite systems, the frequency bands allocated to the non-geostationary orbit satellite are getting less, which would bring the co-frequency interference for data transmission in down-link of non-geostationary orbit satellite network. The ratio C/I between the useful received carrier power and the overall contribution at the receiver input of interference power can show the interference situation. This ratio depends on the system characteristics, such as type of orbits, number of satellites in the constellation, antenna radiation patterns, etc. This paper analyses the problem of co-frequency interference, according to the time-varied character of non-geostationary orbit satellite the paper introduces a method to calculate co-frequency interference. The co-frequency interference is simulated and the results is analyzed, then, visualization of the interfering course is realized which can dynamically display the changes of interference-link during the different simulation periods.