The　proton　transfer　membrane　electrochemical　hydrogenation　reaction　system　was　designed　for　soybean　oil　to　hydrogenate　under　moderate　processing　temperature,　atmospheric　pressure　and　low　current　density.　The　formate　ion　was　regenerated　at　the　cathode　and　acted　as　a　mediator　during　the　hydrogenation　process.　The　effect　of　various　processing　parameters　such　as　temperature,　agitation　speed,　the　amount　of　EDDAB　and　the　oil-water　ratio　on　the　fatty　acid　profile,　iodine　value,　trans　fatty　acid　content,　the　specific　trans　isomerization　index　and　hydrogenation　selectivity　were　investigated.　The　optimum　technological　parameters　of　hydrogenation　were　as　follows:　the　reaction　temperature　60°C,　speed　of　agitation　850　r/min,　the　content　of　EDDAB　3　g　in　100　g　soybean　oil　and　the　oil-water　ratio　0.3　g/g.　Under　the　optimal　technical　conditions,　the　hydrogenated　soybean　oil　was　obtained,　which　contained　13.3%　TFAs,　IV　of　82.73　g　I2/100　g　oil,　AV　of　0.15　mg　KOH/g　oil　and　PV　of　0.070　g/100　g　oil.　Compared　to　the　traditional　hydrogenation　process,　the　application　of　the　diaphragm　electrochemical　hydrogenation　technique　resulted　in　up　to　71%　reduction　in　trans　fatty　acid　when　the　same　level　of　hydrogenation　was　accomplished.