The　valve-less　piezoelectric　pump　is　more　suitable　for　minimization　and　microminiaturization　than　the　valve　piezoelectric　pump,　especially　for　the　Microelectromechanical　System　(MEMS)　because　of　its　simple　structure.　However,　in　order　to　control　the　flow　direction　of　the　fluid　through　the　pump,　some　assembles　have　to　be　attached　outside　the　chamber.　And　it　is　no　doubt　that　these　assembles　will　take　some　space　and　hinder　its　further　microminiaturization.　In　this　paper,　a　novel　valve-less　piezoelectric　pump　with　unsymmetrical　corrugation　chamber　bottom　(UCCB)　is　presented.　It　ingeniously　takes　advantage　of　the　space　of　the　chamber　by　developing　its　bottom　into　a　unsymmetrical　corrugation　shape　along　the　axis　of　the　inlet　and　outlet.　As　a　result,　a　series　of　diffuse　pipes　and　nozzle　pipes　(or　wedge-shaped　pipes),　which　substitute　the　regular　diffuse/nozzle　elements　fitted　outside　the　chamber,　are　alternatively　formed　between　the　unsymmetrical　corrugation　chamber　bottom　(UCCB)　and　the　piezoelectric　vibrator.　The　piezoelectric　vibrator　is　opposite　to　the　UCCB.　And　these　diffuse　pipes　and　nozzle　pipes　are　able　to　force　the　fluid　in　the　chamber　to　flow　along　a　single　direction　when　the　pump　works.　And　then　the　mathematic　model　is　established　to　present　the　relationship　between　the　mean　energy　loss　and　the　now　rate　of　the　pump.　Basing　on　the　mathematic　model,　the　theory　on　the　pump　working　is　analysed.　Finally,　a　real　UCCB　valve-less　piezoelectric　pump　is　manufactured,　and　the　test　with　it　is　carried　out　to　verify　the　theory　above-mentioned.