Prof. Guo Huadong has been engaged in radar remote sensing since the 1970s’. He systematically revealed the interaction mechanism between SAR electromagnetic wave and typical ground objects, established a geometric model of SAR scattering from sand dunes without vegetation, revealed the depolarization mechanism of lava and multi-polarization response of vegetation, and confirmed the penetration of long wave SAR to dry sand. A multi-source remote sensing prospecting theory and model has been established, an all-weather and active and passive remote sensing observation system for major earthquake disasters has been established, and the concept of global change science satellite and moon-based observation has been put forward. Organized the construction of a new earth observation system, completed the land remote sensing application system of Shenzhou Spacecraft, and created China's first digital Earth prototype system. Prof. Guo was awarded the principal investigator of international SAR remote sensing programs including SIR-C/X-SAR, JERS-1 SAR, ERS-1/2 SAR, Radarsat-1/2, Envisat, SRTM, and ALOS ones. He was a member of International SAR Working Group, Chairman of Technical Committee of RICESAT of Asia Remote Sensing Association. In recent 10 years, Prof. Guo has led three national projects focus on new generation SAR for Earth observation.