In order to meet the sealing requirements of downhole flow control valve under high temperature,high pressure and strong corrosion conditions,a U-shaped metal seal ring for radial seal was proposed.The twodimensional finite element analysis model of sealing ring was established by Abaqus software.The maximum Mises stress and the distribution of contact pressure were calculated under prestressing and the downhole actual working condition,and the effect of the initial compression,the sealing ring thickness and the downhole pressure on sealing performance was analyzed.The results show that with the increase of initial compression,the maximum contact pressure is first increased,then decreased and then increased,with the increase of seal ring thickness,the maximum contact pressure is first decreased and then increased,and with the increase of downhole pressure,the maximum contact pressure is increased.When the initial compression is 0.4 mm and the thickness of sealing ring is 3.7 mm,the sealing effect is the best.When the downhole working pressure is 30 MPa,the U-shaped metal sealing ring can meet the sealing conditions and achieve tight sealing.