Three types of thermal barrier coatin gs (TBCs )were prepared by plasma spray(PS)on GH536superalloy substrate with d ifferent layers.One is the traditional TBC wi th Ni22Cr10AlY as bond co at and ZrO 2-8wt%Y 2 O 3 (8YSZ)as top coat,the other two TBCs have a t riplex structure with comp osite layers of 8YSZ +Al 2 O 3 and ZrO 2 ,respectively.The static oxidatio n test and thermal shock tests were cond ucted to evaluate the oxidation kinetics and thermal shock cyclic lifetime of th e TBCs.With the different failure criterions,the failure mechanism of TBCs was discussed.The thermal shoc k resistance of state-of-the-art duplex TBCs is the best.It is indicated that the higher oxidation resis-tance is obtained by using of composite 8YSZ +Al 2 O 3 ceramic layer.It has the better oxid ation resistance if using 8YSZ +Al 2 O 3 as the inner composite layer of TBCs,comparing with as the out layer.