A　super-resolution　imaging　method　using　dynamic　grating　based　on　liquid-crystal　spatial　light　modulator　(SLM)　is　developed　to　improve　the　resolution　of　a　digital　holographic　system.　The　one-dimensional　amplitude　cosine　grating　is　loaded　on　the　SLM,　which　is　placed　between　the　object　and　hologram　plane　in　order　to　collect　more　high-frequency　components　towards　CCD　plane.　The　point　spread　function　of　the　system　is　given　to　confirm　the　separation　condition　of　reconstructed　images　for　multiple　diffraction　orders.　The　simulation　and　experiments　are　carried　out　for　a　standard　resolution　test　target　as　a　sample,　which　confirms　that　the　imaging　resolution　is　improved　from　55.7　mu　m　to　31.3　mu　m　compared　with　traditional　lensless　Fourier　transform　digital　holography.　The　unique　advantage　of　the　proposed　method　is　that　the　period　of　the　grating　can　be　programmably　adjusted　according　to　the　separation　condition.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.