Ultra-precision　measurement　and　manufacturing　need　high-precision　machines,　just　as　a　photolithography　machine　needs　air　bearings.　In　gas　lubrication,　the　use　of　compound　restrictors　with　recesses　has　been　widely　proven　to　be　an　effective　method　to　improve　stiffness,　which　directly　affects　the　accuracy　of　the　machine.　However,　determination　of　the　structural　parameters　of　recesses　is　lacking　in　theoretical　models.　This　paper　has　established　a　mechanical　property　model　for　a　small-scale　guideway,　which　can　respond　to　the　variation　in　force　caused　by　micron-level　changes　in　the　recesses＇　depth.　To　meet　the　requirements　of　high　positioning　accuracy　and　movement　accuracy,　this　paper　puts　forward　a　high-stiffness　guideway　without　an　air　tube.　In　order　to　improve　rotational　stiffness　and　determine　the　structural　parameters　of　recesses,　this　paper　found　a　guideway　with　the　optimal　gradient　depth　of　recesses.　Both　AFVM　(adaptive　finite　volume　method)　research　and　experimental　results　show　that　the　gradient　depth　of　recesses　could　significantly　improve　the　rotational　stiffness　of　guideways　without　air　tubes.