To　meet　the　need　of　high　accuracy,　heavy　load　capacity,　large　stroke　and　micro　stepping,　a　two-dimensional　precision　stage　with　aerostatic　guideways　is　developed.　To　decrease　its　deformation　due　to　the　heavy　load,　the　guideway　with　a　novel　structure　is　designed,　which　has　closed　carriage　with　vacuum　preload.　Based　on　the　guideway,　it　is　constructed　in　co-planar　H　style　configuration.　The　stage　is　driven　by　linear　motors,　and　the　positions　of　the　workpiece　are　encoded　by　length　scales　with　a　resolution　of　50　nm.　The　stroke　of　the　stage　is　320　×　320　mm.　Each　axis　has　a　positioning　accuracy　of　±0.928　μm　and　a　repeatability　of　±0.323　μm.　The　stage　has　a　load　capacity　of　more　than　50　kg,　a　micro　stepping　of　less　than　0.5　μm　and　a　speed　of　more　than　3　m/s.　It　can　be　applied　in　precision　manufacturing　and　measuring.