A novel high-temperature IN690 alloy was prepared via a hot extrusion process. The Gleeble-3500 thermal simulation test machine was used to perform isometric compression tests to study the effects of different temperatures, strain rates, and deformations on the dynamic recrystallization (DRX) of IN690 alloy. Using metallographic microscopy and electron backscatter diffraction (EBSD), the metallographic structure, grain orientation, grain boundary distribution and grain orientation difference of the IN690 alloy before and after thermal deformation were systematically analyzed. The true stress-true strain curve obtained using the test showed that as the temperature decreased or strain rate increased, the IN690 alloy flow stress increased. The major softening mechanisms during the IN690 alloy deformation were the dynamic recovery (DRV) and DRX; The proportions of high-angle grain boundary increased with an increase in the true strain or a decrease in the strain rate due to the the DRX nucleation for a large true strain or low strain rate.