A　test　bench　of　a　multistage　centrifugal　pump　was　constructed　using　R123　as　working　fluid　in　simulative　organic　Rankine　cycle　(ORC)　conditions.　Experimental　results　of　the　pump　under　various　operating　conditions　were　obtained　based　on　controlled　working　frequency　and　mass　flow　rate.　The　effect　of　the　key　pump　parameters　on　the　ORC　performance　was　analyzed　in　this　study.　In　addition,　the　control　strategy　of　the　pump　was　presented.　Results　show　that　the　overall　pump　efficiency　was　between.15%　and　65.7%.　The　outlet　pressure,　pump　efficiency,　and　ORC　thermal　efficiency　increased　with　the　working　frequency　of　the　pump.　The　mass　flow　rate　needed　to　be　regulated　as　the　frequency　became　increasingly　high.　The　maximum　thermal　efficiencies　of　the　ORC　system　corresponding　to　various　working　frequencies　of　the　pump　were　observed.　Furthermore,　back　work　ratio　(BWR)　can　reach　up　to　0.45　with　the　increase　of　the　evaporating　temperature　of　the　ORC　system.　Pumping　power　should　not　be　neglected　for　small-scale　ORC　applications,　and　pump　efficiency　assumptions　should　be　dependent　on　experiments.　Low　pump　efficiency　affected　the　increase　of　the　thermal　efficiency　and　net　power　of　the　ORC　system.　The　superheat　degree　was　also　discussed.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.