The 3400–3600 MHz band is one of the most important candidate frequency bands for the rollout of 5G system. However, the co-existence between 5G system and fixed-satellite service (FSS) in this frequency band is one of the most challenging problems for both academic researchers and industry engineers. In this paper, the saturation interference from 5G base stations to the existing FSS above 3600 MHz is analyzed and the coexistence solution is achieved, which can reduce the interference and guarantee the coexistence between 5G system and FSS. Furthermore, the Monte Carlo simulation, laboratory test and field test are carried out to verify the coexistence solution. Results show that an isolation distance of 1–2 km is required to avoid the saturation interference in terms of the adjacent bands scenario. To further reduce the isolation distance to 50 m, additional isolation of 35 dB will be necessary, which can be fulfilled by installing a filter at the input port of LNB from a real implementation perspective.