The　Intra-Aorta　Pump　is　a　novel　LVAD　assisting　the　native　heart　without　percutaneous　drive-lines.　The　Intra-Aorta　Pump　is　emplaced　between　the　radix　aortae　and　the　aortic　arch　to　draw-off　the　blood　from　the　left　ventricle　to　the　aorta.　To　predict　the　change　of　pressure　drop　and　blood　flow　along　with　the　change　of　pump　speed,　a　nonlinear　model　has　been　made　based　on　the　structure　and　speed　of　the　Intra-Aorta　Pump.　To　do　this,　a　nonlinear　electric　circuit　for　the　Intra-Aorta　Pump　has　been　developed.　The　model　includes　two　speed　dependent　current　sources　and　flow　dependent　resistant　to　simulate　the　relationship　between　the　pressure　drop　of　the　Intra-Aorta　Pump　and　the　flow　through　the　pump　along　with　the　change　of　pump　speed.　The　pressure　drop　and　blood　flow　is　derived　by　solving　differential　equations　with　variable　coefficients.　The　parameters　of　the　model　are　determined　by　experiment,　and　the　results　of　the　experiment　show　that　these　parameters　change　along　with　the　change　of　the　pump　speed　distinctness.　The　accuracy　of　the　model　is　tested　experimentally　on　a　test　loop.　The　comparison　of　the　prediction　data　derived　from　the　model　with　the　experimental　data　shows　that　the　error　is　lest　than　15%.　The　experimental　results　showed　that　the　model　can　predict　the　change　of　pressure　drop　and　blood　flow　accurately.　©　2009　Springer-Verlag.