Gate oxide reliability face a big challenge in high temperature automotive application (auto-grade 0). In this paper, we fully discuss the physical mechanism of oxide trap interaction and point out the oxide reliability weakness. It is found the unexpected TDDB behavior at high temperature, include strong SBD, the relationship of voltage acceleration change, and non-linear temperature effect. In addition, the AC/DC effect found more obvious recovery effect. Finally, for mass production, we also import the confidence level usage to give a reasonable lifetime margin for mass production.