The molecular dynamics method is employed to simulate motions of monovacancies in the ordered intermetallic compound NiAl using Finnis-Sinclair N-body potentials.It is shown that the antistructure bridge mechanism is important at compositions deviated from stoichiometry, and near the stoichiometry, the six-jump cycle, the staight ［100］-type for Al vacancy and ［110］-type cycle for Ni vacancy, are energetically favorable. The calculated results, which are consistent with experimental measurement, clarify the recovery behavior of defects in NiAl quenching experiment.