A fatigue test apparatus for thin workpiece includes a supporting module, a driving mechanism, a first connecting module, a second connecting module, a first holding post, a second holding post and a computer system. The first and second connecting modules are respectively fixed to two sides of the supporting module. Ends of the first holding post and the second holding post are fixed to the first and second connecting modules. The computer system electronically connects with and controls the driving mechanism. The first holding post and the second holding post are drive to rotate by the driving mechanism.