The　pressure-driven　Poiseuille　flow　of　a　rarefied　gas　in　micro-channel　and　micro-tube　is　analyzed　by　the　26　moments　method,　and　the　profiles　of　velocity　and　pressure　are　obtained.　Numerical　analysis　shows　the　deviation　of　the　pressure　distribution　from　a　linear　pressure.　The　larger　the　Kn　number,　the　smaller　deviation　of　the　pressure.　For　the　micro-tube,　when　the　Kn　number　increases,　there　appears　two　peaks　in　the　distribution　of　the　streamwise　velocity.　The　numerical　results　are　in　good　agreement　with　available　DSMC　and　LBM　data.