In order to research the influences of ring carrier and oil cooling gallery on the piston reliability, the simulations of piston with the ring carrier of same type and different structures were conducted. The temperature of piston with ring carrier was first measured by hardness plug test at rated condition, which was taken as the boundary conditions of simulation. Then thermal and mechanical coupling calculations were carried out by considering the influences of temperature, incylinder pressure and combustion force, and then the deformation and stress distribution of the key position of piston were acquired. Finally, the high cycle fatigue of piston was calculated by using fatigue analysis software. Compared with the piston with ring carrier and piston with oil cooling gallery in ring carrier respectively, the temperature at the root of first ring groove for the piston with oil cooling gallery in ring carrier decreased by 6.5% and 16%,its thermal stress decreased by 33% and 15% and its mechanical stress decreased by 31% and 11%. The results show that the structure of oil cooling gallery in ring carrier can effectively reduce the stress caused by thermal load and mechanical load and hence avoid the phenomenon of stress concentration. In addition, the new piston can enhance the wear resistance of ring groove and hence the service life for the lower side of ring groove prolongs.