Citric　acid　(CA)　was　used　to　modify　graphitic　activated　carbon　(AC)　to　improve　the　ruthenium　distribution　and　the　catalytic　activity　of　Ru/AC　catalyst.　The　influence　of　CA　on　the　texture　of　AC　and　Ru/AC,　Ru　dispersion　and　catalytic　activity　were　investigated.　Transmission　electron　microscopy　(TEM),　thermogravimetric　analysis　(TGA),　CO　pulse　chemisorption　and　N2　physisorption　indicated　that　minor　amounts　of　citric　acid　significantly　decreased　the　surface　area　of　AC　and　increased　the　content　of　oxygen-containing　functional　groups　on　the　surface　of　AC.　This　is　the　result　of　preferential　adsorption　of　CA　in　AC　micropores　which　improves　the　particle　distribution　of　Ru.　The　optimal　loading　sequence　is　CA　followed　by　RuCl3.　A　suitable　content　of　CA　in　Ru/AC　catalysts　has　a　remarkable　influence　on　the　activities　of　Ru/AC　catalysts　at　low　reaction　temperature.　The　greatest　increase　of　activity　was　21.4%　for　the　Ru/AC　catalysts　treated　with　CA.　©　Editorial　office　of　Acta　Physico-Chimica　Sinica.