A　novel　valveless　piezoelectric　pump　with　unsymmetrical　ridges　is　presented　at　first.　It　ingeniously　utilizes　the　inner　space　of　its　chamber　by　developing　its　chamber　bottom　into　unsymmetrical　ridges　along　the　direction　of　the　inlet　and　outlet　of　the　pump.　Hence,　a　series　of　cuneiform　channels　are　asymmetrically　and　alternately　formed　between　the　unsymmetrical　ridges　and　the　piezoelectric　vibrator,　which　enables　the　pump　to　form　a　one-way　flow　instead　of　the　function　of　the　traditional　diffuse　or　nozzle　elements　fitted　outside　the　chamber.　Then,　by　analyzing　the　vibration　of　the　piezoelectric　vibrator,　the　vibration　deformation　function　and　the　equation　of　volume　change　are　established.　Meanwhile,　the　theoretical　equation　of　the　pump　flow　rate　is　established.　Finally,　a　real　valveless　piezoelectric　pump　with　unsymmetrical　ridges　is　manufactured,　and　the　flow　rate　of　the　pump　is　measured　through　experiments.　It　is　proved　that　the　theory　is　rational　and　correct　by　comparing　the　experimental　flow　rate　and　the　theoretical　flow　rate.　In　addition,　for　calculating　the　theoretical　flow　rate,　the　positive　and　converse　flow　resistance　coefficients　of　unsymmetrical　ridges　are　measured　through　experiments,　when　one　slope　angle　of　the　unsymmetrical　ridges　is　90°　and　another　is　changing　from　20°　to　60°,　respectively.　©　Higher　Education　Press　and　Springer-Verlag　2007.