The high radiation resistance and long time stability of Gd2Zr2O7 ceramics make it a promising candidate for high level waste (HLW) immobilization materials. In this study, single phase nanocrystalline Gd2Zr2O7 was successfully synthesized and consolidated at temperatures around 1050 °C for only 1 min by flash sintering for the first time. The phase evolution and microstructural development during flash sintering were systematically studied and compared with the conventionally sintered samples. The flash sintered Gd2Zr2O7 exhibit defect fluorite structure, and a following heat treatment at 1400 °C could transform the Gd2Zr2O7 ceramics from defect fluorite phase into pyrochlore phase. The MCC-1 leaching test shows that the flash sintered Gd2Zr2O7 samples exhibit good aqueous durability.