Abstract: To investigate the compression springback properties of Inconel718 alloy O-ring used to seal pressure vessels, a series of experiments based on small O-ring specimens cut from alloy tubes were conducted. Experimental results show that temperature, loading history and axial-length have small effects on the springback properties of the O-ring specimens. At room temperature, it is found that the springback value of an O-ring specimen increases with an increase in the compression ratio as a parabola if the compression ratio is between 6% and 30%. The sealing property of the O-ring is good in this ratio range. When the compression ratio exceeds 30%, the springback value decreases. Environmental temperature higher than 600℃ leads to the collapse of the initial contact surface of an O-ring specimen during compression test. In order to simulate the springback properties of O-ring, 2D and 3D finite element analyses were carried out with ANSYS program using different constitutive models. It is shown that the simulation results are in good agreement with the experimental results.