Instantaneous　wave-free　ratio　(iFR),　an　invasive　index　of　coronary　artery　tree,　can　evaluate　the　functional　performance　of　vascular　stenosis　without　pharmacological　vasodilators.　The　noninvasive　assessment　of　diameter　stenosis　(DS)　obtained　from　coronary　computed　tomography　angiography　(CTA)　has　high　false　positive　rate　in　contrast　to　iFR.　The　aim　of　this　study　was　to　develop　a　numerical　simulation　method　that　predicts　the　iFR　and　noninvasively　assess　the　myocardial　ischemia.　Based　on　the　CTA　images,　a　patientspecific　three-dimensional　model　of　the　aorta　and　coronary　arteries　were　reconstructed.　A　stenosis　was　created　in　the　left　anterior　descending　artery　(LAD)　by　reducing　the　DS　of　geometric　model　(40%,　50%,　60%,　75%　and　90%).　The　patient-specific　LPM　boundary　condition　were　set　up　to　compute　iFRct　value　during　the　wave-free　period　at　the　resting　condition.　The　computed　pressure　and　flow　of　coronary　artery　were　realistic　as　compared　to　literature　data.　In　contrast　to　invasive　iFR,　the　iFRct　can　make　a　cost-benefit　balance　in　terms　of　clinical　cost　and　patient＇s　health.