Abstract: Using space platforms as carriers,spatial information network(SIN)is a new kind of net-work system that implements real-time data acquisition,fast network transmission and informationprocessing.Through real-time data access/transmission,networks interconnection and cooperativedata processing,SIN could realize the integrated application and collaborative service of satellite re-mote sensing,satellite navigation and satellite communication.Firstly,the concept,function andcharacteristic of space information network are introduced.Then the significance and necessity of con-struction of China’s SIN are represented after an analysis of development of SIN at home and abroad.Finally,the research objectives and scientific issues for China’s SIN construction are discussed.