The work aims to study the effects of different ceramic materials on the piston temperature and thermal stress. With MgO-partially stabilized zirconia ceramic (Mg-PSZ) and yttria-partially stabilized zirconia ceramic (Y-PSZ) as objects of study, plasmas Mg-PSZ and Y-PSZ were sprayed on the top of AlSi alloy piston. The effects of two different coating materials on piston temperature and thermal stress field were studied, contrastive analysis was performed to change of piston temperature field and thermal stress field with ceramic coating or not. Compared with the uncoated piston, surface temperature of Mg-PSZ coating piston and Y-PSZ coating piston increased obviously by 50.49% and 34.81% respectively while corresponding maximum substrate temperature decreased by 28.49% and 17.34% respectively. Meanwhile, distribution of temperature and thermal stress on the Mg-PSZ coating piston was same as that of Y-PSZ coating piston, so was the distribution of piston substrate and uncoated piston. Both the Mg-PSZ coating piston and Y-PSZ coating piston can lead to the increase of the surface temperature and the stress. Y-PSZ has greater impact on substrate temperature while Mg-PSZ has greater impact on stress.