In this paper, the high temperature oxidation resistance of YAG/8YSZ double ceramic and 8YSZ single ceramic thermal barrier coatings system were analyzed. The bond-coat (NiCoCrAlY) was deposited on a 310S heat-resistant stainless steel substrate by detonation gun spraying, and YAG/8YSZ double ceramic and 8YSZ single ceramic thermal barrier coatings were deposited on the bond-coat by air plasma spraying (APS), respectively. The cross-section and surface characteristics of the coating were analyzed by SEM and XRD before and after oxidation. The oxidative weight gain kinetics, microstructure, phase of the YAG ceramic layer, and the TGO growth process and growth kinetics of the two thermal barrier coating systems were comparatively investigated after isothermal oxidation at 1100 °C. The results showed that the YAG ceramic layer shows no obvious phase transformation after isothermal oxidation at 1100 °C for 200 h, and the porosity was slightly reduced. The oxidation weight gain rate and TGO growth rate of YAG/8YSZ double ceramic layers system was 1.7 times and 1.4 times lower than that of 8YSZ single ceramic layer system, respectively. The double ceramic layer system showed a low the β-NiAl phase consumption rate and the island oxide growth rate, which resulted in a better high temperature oxidation resistance.