Apparatus and method for transferring a substrate are disclosed. The substrate transfer apparatus includes: a substrate conveyance assembly disposed between a mechanical arm and a wafer stage, the substrate conveyance assembly including a substrate loading conveyor and a substrate unloading conveyor parallelly arranged in a first direction, each of the substrate loading conveyor and the substrate unloading conveyor configured for transferring a substrate between the wafer stage and the mechanical arm along a second direction perpendicular to the first direction; an integral frame; and a transition air suspension assembly fixed to the integral frame at the end thereof proximal to the wafer stage, the transition air suspension assembly being able to engage with either of the substrate loading conveyor and the substrate unloading conveyor for producing an air film to levitate the substrate during the conveyance of the substrate by the substrate loading conveyor or the substrate unloading conveyor.