An　alignment　technique　adopting　a　pair　of　special　slant　gratings　is　presented　for　room-temperature　imprint　lithography.　The　transmittance　characteristic　of　alignment　marks　based　on　Fourier　optics　is　also　investigated.　The　analysis　shows　that　the　alignment　signal　is　a　sine　wave.　The　vicinity　of　alignment　position　is　a　linear　region　of　a　steep　slope.　The　sensitivity　of　alignment　signal　in　the　area　is　high　and　it　is　suitable　for　multi-layer　alignment.　Based　on　the　linear　relation　between　signal　and　displacement,　a　calculation　model　for　the　initial　alignment　signal　is　given.　Since　due　to　the　existence　of　resist　is　and　the　surface　reflectance　of　wafer　varies　with　displacement,　a　more　reasonable　and　accurate　model　is　developed　to　describe　the　optical　effect　of　the　resist　film　and　to　calculate　the　alignment　signal.　Different　average　thickness　of　resist　can　cause　different　alignment　signals.　The　results　show　that　the　resist　thickness　should　be　reduced　properly　for　getting　high　sensitive　alignment　signal.