The oxidation behavior of Ti3AlC2-20TiB2 composite was studied at 500 °C–900 °C in air. The composite showed a very low oxidation rate and followed a logarithmic oxidation law. The in-situ incorporation of TiB2 suppressed the anomalous rapid oxidation of the substrate Ti3AlC2 occurred near 600 °C by forming a protective B2O3 glass layer, and also improved the oxidation resistance of the MAX phase at intermediate-temperature.