A system for evaluating fractional flow reserve after implantation of a virtual stent, which is capable of performing the following functions: receiving geometric parameters of a segment of a vessel, the geometric parameters comprising a first, a second and a third geometric parameter calculating a reference lumen diameter function and the diameter stenosis rate before implantation of the virtual stent on the basis of the geometric parameters and the distance between a point on the vascular segment and a reference point by using the proximal end point as the reference point receiving the position for implanting the virtual stent calculating geometric parameters of the virtual vascular lumen, a difference function between the geometric parameters of the virtual vascular and the diameter stenosis rate after implantation of the virtual stent on the basis of the third geometric parameter, the position for implanting the virtual stent and the reference lumen diameter function taking the derivative of the difference function between the geometric parameters after implantation of the virtual stent at different scales, and obtaining the fractional flow reserve on the basis of multi-scale difference derivative functions and the maximum mean blood flow velocity after implantation of the virtual stent. The change of the diameter stenosis rate and the maximum mean blood flow velocity after implantation of the virtual stent are used to evaluate the fractional flow reserve after implantation of the virtual stent by the multi-scale calculation method.La présente invention décrit un système dévaluation de la réserve de débit fractionnaire après limplantation dune endoprothèse virtuelle, qui est susceptible dexécuter les fonctions suivantes : recevoir les paramètres géométriques dun segment dun vaisseau, les paramètres géométriques comprenant un premier, un deuxième et un troisième paramètres géométriques, le calcul dune fonction de diamètre de lumière de référence et du degré de st
