The　natural　frequency　at　lower　orders　for　hydrostatic　supported　worktable　system　may　easily　give　rise　to　vibration　as　in　resonance　with　excitation　frequency.　This　paper　is　concerned　with　the　geometrical　optimum　design　and　dynamic　modal　analysis　for　system　with　hydrostatic　oil　fluid　and　worktable　simultaneously.　The　variations　of　eigenfrequency,　respect　to　oil　film　thickness,　outer　radius　of　worktable,　recess　shape　and　number,　were　discussed.　The　results　show　that,　under　linear　increment/decrement　of　geometry　dimension,　frequency　increase/decrease　but　in　nonlinear　regularity.　Therefore　there　exists　an　optimum　dimension　resulting　the　optimum　frequency　that　deviate　from　the　rotary　frequency　at　work　and　its　multiple　ones.　Then　two-phase　optimization　strategy　was　effectively　programmed　to　get　involved　with　finite　element　analysis　software.　It　is　theoretically　critical　to　get　the　optimum　parameter　of　hydrostatic　supported　worktable　on　how　and　practically　important　to　guide　the　design　in　engineering.　©　(2012)　Trans　Tech　Publications,　Switzerland.