A　valueless　piezoelectric　pump　with　Y-elements　is　assembled　by　installing　two　inverted　Y-shape　tees　to　the　chamber,　which　is　composed　inlet,　outlet,　piezoelectric　vibrator,　chamber　and　other　parts.　This　pump　has　no　chemical　and　electromagnetic　pollution　sources,　nor　periodic　valves　opening　or　closing.　It　also　characters　potentiality　to　be　miniaturized　and　integrated.　This　pump　facilitates　to　transfusing　living　cells　and　macromolecular　compound　because　only　lower-intensity　eddy　field　occurs　when　pump　fluid　flows　through　the　Y-elements.　Firstly,　the　structure　of　the　new　valueless　piezoelectric　pump　with　Y-elements　is　presented.　Then,　pressure　distribution　and　velocity　vector　distribution　in　the　Y-elements　are　simulated　by　means　of　finite　volume　method,　which　proves　when　fluid　flows　through　Y-elements　the　eddy　field　is　far　lower　than　that　in　diffuser/nozzle　elements.　Simulations　also　show　that　the　fluctuations　of　the　pressure　and　velocity　in　Y-elements　are　much　lower.　Thirdly,　the　equation　of　volume　change　is　built　through　analyzing　vibration　of　the　piezoelectric　vibrator.　And　the　theoretical　relationship　between　the　flow　rate　and　the　frequencies　of　piezoelectric　vibrator　is　established.　Finally,　through　the　flow　test　this　device　with　Y-elements　is　proved　to　have　the　characteristics　of　pump,　thus　proving　the　correctness　of　the　theoretical　model　presented　above.