Abstract: Traditional single-hop link is used in deep space communication,which may be greatly affected by kinds of factors in earth's atmosphere.Because of the large difference between the free space link,simply improving carrier frequency can not guarantee the reliability of communication.GEO satellite were used in space as relay station,a double-hop system was constructed from deep space explorer to ground stations,which adopted high frequency in free space link and about 10GHz frequency in the second hop link to evade gases' influences.Comparing with the single-hop system,the double-hop one obtained more ratio of signal-to-noise and channel capacity and less error rate and also improved system reliability.Existing GEO ground antenna's can meet the requirements of the deep space communication missions.