Considering the influence of heat and deformation on the self-vibration stability of oil-gas two-phase dynamic pressure seal,a mathematical model of self-vibration stability of oil-gas two-phase dynamic pressure seal was established.By using the fluidsolidthermal coupling finite element method,the influence of the oilgas two-phase dynamic pressure seal parameters such as oil-gas ratio,rotational speed,differential pressure and O-ring damping on the axial and angular self-vibration-stability was studied.The results show that the axial sel-vibration stability is better and the angular selfvibration vibration stability is poorer under lower speed,and the two are opposite under higher speed.The axial selfvibration stability is poorer and the angular selfvibration stability is better under lower O-ring damping,and the two are opposite under higher O-ring damping.Therefore,under the condition of extreme speed and extreme O-ring damping,the axial or angular critical frequency is small,which is not conducive to the selfvibration stability of the oilgas twophase dynamic pressure seal.The greater the pressure difference,the better the axial selfvibration stability,and the worse the angular selfvibration stability.With the increase of oilgas ratio,the axial critical frequency is decreased and the axial critical mass is increased.When the oilgas ratio is between 0.1 and 0.15,the critical frequency,critical mass,and moment of inertia are larger,and the comprehensive selfvibration stability of the seal is better