Aimed at the variation of contact stress of rubber O-ring in double floating seal,the two-dimensional axial symmetric nonlinear model of double floating seal was built,and the stress of O-ring was calculated by finite element method.The stress variation of O-ring under different compression ratio,different inclined angles of the floating seal seat and floating seal ring and different friction coefficient was analyzed.The results show that the maximum stress of rubber O-ring increases linearly with the increase of compression ratio.The high stress distribution area of O-ring is expanded as the compression ratio increasing,and it diffuses from the contact area to the middle area of the O-ring.The friction coefficient has little effect on the stress of O-ring,while the inclined angles of the floating seal seat and floating seal ring have great influence on the equivalent stress and contact pressure of O-ring.With the increase of the inclined angles of the floating seal seat,the overall equivalent stress tends to decrease,the contact pressure first decreases and then increases slowly,while the overall change of the shear stress is small.With the increase of the inclined angles of the floating ring,the equivalent stress and contact pressure increase gradually,and the shear stress curve fluctuates up and down,but the overall change is not obvious.The optimal angles of the floating seal seat and ring of double floating seal are determined,which provides important guidance for the structure design of double floating seal.