In　order　to　learn　more　about　the　characteristics　of　a　valveless　piezoelectric　pump　with　Y-shape　tubes,　the　flow　rate　and　fluid　flowing　state　in　the　pump　were　simulated　and　analyzed.　The　commercial　finite　element　software　CFX　was　employed　to　simulate　the　fluid　flowing　state　in　the　pump.　The　simulative　results　reveal　that　the　pressure　in　the　pump　chamber　varies　mildly,　and　the　vortex　in　the　pump　chamber　hardly　does　harm　to　the　results　of　transporting　living　cells　and　long-chain-marcomolecule　cells.　A　valveless　piezoelectric　pump　was　made,　and　the　variational　principle　of　pressure　drop　between　the　outlet　and　the　inlet　of　the　pump　was　explored　by　changing　the　geometrical　dimensions　of　the　Y-shape　tubes.　The　experimental　results　show　that　the　pressure　drop　decreases　when　the　angle　between　two　branches　increases,　and　reaches　the　minimum　when　the　sum　of　the　width　of　two　branches　is　close　to　that　of　the　main　tube,　the　pressure　drop　reaches　a　maximal　of　725　Pa　when　the　branch　angle　is　5°　and　the　branch　width　is　1.2　mm.