Gas burner is the key component of coal-water slurry gasifier system. However, due to the sulfidation at high temperature, gas burner often fails in advance, which affects the stable operation of the system. In this work, Al-Mo coatings are deposited by plasma spraying with a Mo bonding layer. The sulfidation and oxidation behavior of the Al-Mo coatings is studied and compared with those of Mo coatings and Inconel 600 alloy at 973 K, 1073 K and 1173 K. It is found that both the high-temperature sulfidation resistance and the high-temperature oxidation resistance of Al-Mo coatings are superior to those of Mo coatings. The high temperature sulfidation resistance of coatings is better than that of Inconel 600 alloy. Plasma-sprayed Al-Mo coatings with a Mo bonding layer are promising candidates for the corrosion protection of steels in a sulfur/oxide-rich atmosphere.