To　study　the　performance　and　selection　of　the　working　fluid　pump　in　organic　Rankine　cycle　(ORC)　waste　heat　recovery　system　for　vehicle　engines,　a　test　bench　of　a　multistage　centrifugal　pump　was　constructed　using　R123　as　working　fluid　in　a　condition　of　simulative　ORC　waste　heat　recovery　system　for　vehicle　engines.　Experimental　results　of　the　multistage　centrifugal　pump　under　various　operating　conditions　were　obtained　based　on　controlled　working　rotational　speed　(870-2900　r·min-1)　and　working　fluid　flow　rate　(0.20-5.00　m3·h-1).　The　interaction　of　the　key　pump　parameters　and　their　effect　on　the　ORC　performance　were　analyzed　in　this　paper.　In　addition,　the　feasibility　of　the　multistage　centrifugal　pump　applied　to　the　ORC　waste　heat　recovery　system　for　vehicle　engines　was　verified　and　the　optimal　working　point　parameters　were　also　determined.　Results　showed　that　the　overall　pump　efficiency　of　multistage　centrifugal　pump　was　between　15.00%　and　65.70%.　The　outlet　pressure,　pump　efficiency　and　ORC　thermal　efficiency　increased　with　the　increase　of　the　rotating　speed　of　the　pump.　The　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,　the　practical　back　work　ratio　(BWR)　can　reach　up　to　0.45　with　the　increase　of　the　evaporating　temperature　of　the　ORC　system.　And　the　thermal　efficiency　can　reach　up　to　10.50%　when　the　rotating　speed　of　multistage　centrifugal　pump　was　2900　r·min-1.　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.　©　All　Right　Reserved.