For　size　effect　on　solid-liquid　interface　of　hydrostatic　bearing　oil　film　gap　flow　in　two-dimension,　fluid　dynamic　method　is　applied　to　investigate　the　influence　of　size　effect　on　bearing　capacity,　dynamic　stiffness　and　other　performances.　With　the　consideration　of　size　effect,　Reynolds　equation　is　modified　by　adopting　velocity　slip　boundary　condition　into　Reynolds　equation　.　The　sensitivity　factors　are　used　to　make　a　quantitative　and　qualitative　analysis.　Numerical　simulation　results　show　that　size　effect　will　affect　bearing　performances　to　a　certain　degree　and　the　effect　curve　of　size　effect　on　bearing　performances　are　given.　The　four　maximum　oil　film　pressures　reduce　with　the　increase　of　slip　length.　The　maximum　sensitivity　of　bearing　capacity　is　81.94%.