An　off-axis　digital　holographic　reconstruction　method　with　fractional　Fourier　transform　domain　filtering　is　proposed.　The　theoretical　expression　and　analysis　of　the　characteristics　of　fractional-transform-domain　filtering　are　given.　It　is　proven　that　the　filtering　in　a　lower　fractional-order　transform　domain　can　utilize　more　high-frequency　components　than　that　in　a　conventional　Fourier　transform　domain　under　the　same　size　of　filtering　regions.　In　simulation　and　experiment,　the　results　demonstrate　that　the　reconstruction　imaging　resolution　can　be　improved　by　filtering　in　the　fractional　Fourier　transform　domain.　The　presented　fractional　Fourier　transform　filtering　reconstruction　provides　a　novel　(to　our　knowlede)　optional　way　for　off-axis　holographic　imaging.　　©　2023　Optica　Publishing　Group.