In deep geological drilling， complex downhole conditions raises demanding requirements on drilling performance and reliability of drilling tools. Wear-resistant and corrosion-resistant amorphous coating on the surface of drilling tool steel can effectively improve its service life. Among them， Fe based amorphous alloy coating has important application value and good economic benefits because of its excellent corrosion resistance and wear resistance， strong amorphous formation ability and other advantages. An amorphous alloy coating composed of Fe₄₈Cr₁₅Mo₁₄C₁₅B₆Y₂ （at.%） was prepared on the 35CrMo substrate by air plasma spraying （APS） technology， and subjected to vacuum heat treatment at different temperatures. The effects of heat treatment at different temperatures on the basic properties and wear failure mechanism of the coatings were investigated. The results showed that vacuum heat treatment produced a large amount of hard phase and homogenized the composition； thus， improving the wear resistance of the coating. With the increase of heat treatment temperature， the coating wear rate decreases gradually. Compared with the coating either without heat treatment or with 750℃ heat treatment， the coating with heat treatment at 850℃ had the best wear resistance， and the wear rate was only 16.7% of that of Fe based amorphous coating without heat treatment. Failure mechanisms of the coatings either with or without heat treatment all include adhesion wear， abrasive wear， fatigue wear and oxidation wear.