To　find　out　the　effects　of　geometry　of　the　oil　seal　edge　on　flow　field　and　load　capacity　of　NC　machine＇s　hydrostatic　oil　cavity,　computational　fluid　dynamics　(CFD)　simulation　is　applied.　Results　indicate　that　the　height,　length,　angle　and　microstructure　of　the　oil　seal　edge　have　important　effects　on　the　vortices　of　flow　field　and　load　capacity.　By　changing　these　factors,　the　pressure　of　the　flow　field　and　the　load　capacity　can　be　improved.　The　results　can　be　used　to　optimize　the　design　of　geometry　of　hydrostatic　oil　cavity　and　improve　its　performance.