The　intra-aorta　pump　is　a　novel　left　ventricular　assist　device　(LVAD)　that　assists　the　heart　without　the　need　for　percutaneous　wires　and　conduits.　It　is　implanted　between　the　radix　aortae　and　the　aortic　arch　to　avoid　damage　to　the　aortic　valve.　To　predict　the　mean　pressure　head　and　blood　flow,　a　nonlinear　lumped　parameter　model,　which　does　not　need　the　parameters　of　the　circulatory　system,　is　established.　The　model　includes　a　speed-controlled　current　source,　an　internal　resistor,　and　an　inductance　for　simulating　the　pressure-flow　rate　relationship.　The　speed-controlled　current　source　is　used　to　represent　the　blood　flow　caused　by　the　kinetic　energy　from　the　impeller,　the　internal　resistor　is　used　to　stimulate　the　resistance　character　of　the　radial　clearance　of　the　intraaorta　pump,　and　the　inductance　is　used　to　model　the　inertia　of　the　blood　that　passes　through　the　radial　clearance.　Each　part　of　the　model　has　clear　physical　significance,　which　is　helpful　for　extending　the　model　to　other　blood　pumps.　It　can　generate　all　status　of　the　pump　from　suction　to　pulmonary　congestion.　The　model　is　summarized　as　a　function　of　the　pressure　head,　the　blood　flow,　and　rotational　speed　of　which　the　values　of　parameters　in　the　model　are　determined　by　experiment.　The　model　and　prediction　method　are　tested　experimentally　on　an　in　vitro　mock　loop.　A　comparison　of　the　predicted　pressure　head　obtained　from　our　model　with　experimental　data　shows　that　our　model　can　predict　the　differential　pressure　accurately　with　error　＜5%　for　all　experimental　conditions　over　the　entire　range　of　intended　use　of　the　intra-aorta　pump.　ASAIO　Journal　2010;　56:504-509.