The mechanical propriety,especially the compressionresilience characteristic and contact properties,of metallic Oring has a significant influence on the stability of the connection of the sealing system.By considering the composite structure,elasticplastic characteristics and working conditions of sealing ring,a FEA model of the metallic Oring used in reactor pressure vessel was built for the purpose of mechanical properties study.Compressionresilience characteristic,stressstrain characteristic,and influence of silver coating on different mechanical properties were analyzed and corresponding experiments were conducted for verification.Results show that the calculation results of FEA model and experiment data have good consistency.The sealing performance reduces as the result of a compression ratio either too large or too small.The compressionresilience process can be divided into 4 stages:elastic deformation,plastic deformation,flange contact and resilience,the resilience compensation property is determined by the compression ratio.The silver coating mainly contributes to the homogenization of contact pressure but has small influence on the overall compressionresilience characteristic.