Aimed at the problem of service life shortening of mechanical seal of slurry pump in phosphoric acid plant due to end face deformation,taking the seal ring of back-to-back double mechanical seal of slurry pump as the research object,a three-dimensional thermal-stress coupling calculation model of the seal ring was established by using the integral method according to the actual working conditions.The temperature field distribution and end face deformation of seal ring was studied,and the effect of thermal-stress deformation of seal ring on the normal operation of mechanical seal under different working conditions was analyzed.The results show that the highest temperature of the seal ring occurs at the inner side of the static ring,and the temperature gradually decreases along the radial direction toward the outer side of the static ring.The environmental temperature has a significant impact on the thermal-stress deformation of the seal ring,and the mechanical seal is more prone to failure at high temperature environment.Under the influence of thermal-stress coupling,the sealing face changes from parallel surface to convergence surface,resulting in rapid wear of the sealing surface and the increase of leakage.According to the deformation shape of the end face,the mechanical seal can be considered to be transformed into a non-contact mechanical seal,so as to improve its service life.