In order to meet the requirements of high-speed data rates at any time in any region， and cope with the increasing competition for space resources among countries， the low earth orbit （LEO） satellite Internet， which is included in new infrastructure construction category， has become one of the most promising solutions. In this paper， based on the design concept of integrating three satellite application functions together，that is， satellite communication，satellite navigation enhancement and satellite remote-sensing，we put forward a system architecture that takes “inter-satellite networking + high speed processing on board + beam hopping” as its main technical characteristics. Through the analysis of key technologies such as inter-satellite laser communication， high-speed satellite routing processing on board， and broadband beam-hopping， the proposed architecture provides a ground verification method for this LEO satellite system containing the first launched satellite. The satellite network architecture， critical technical solutions and in-orbit verification results proposed in this paper can serve as a useful exploration and reference for the construction and development of satellite Internet in China.