A heat treatment method for a titanium-aluminum (TiAl) intermetallic includes the following steps: providing a TiAl intermetallic casting material; performing a first-stage heat treatment on the TiAl intermetallic casting material, where the TiAl intermetallic casting material is heated until a metallographic structure thereof is transformed into the α+γ phase, and is then cooled to room temperature to form a transitional casting material; and performing a second-stage heat treatment on the transitional casting material, where the transitional casting material is heated until a metallographic structure thereof is transformed into the α single phase, and is then cooled to room temperature to form a TiAl intermetallic.