Abstract: The present invention provides a rapid calculation method and system for a plaque stability index based on a medical image sequence. The system includes an image acquisition module, an image receiving module, an image processing module, a finite element calculation module and a result visualization module. The image acquisition module and the image receiving module are configured to acquire, receive and transmit a dynamic two-dimensional vascular image sequence; the image processing module is configured to acquire a space-transformational displacement field function by taking a local feature or a global image as a registration based on dynamic information of real-time deformation of an artery under a two-dimensional image; and the finite element calculation module is configured to acquire a time-dependent vascular lumen diameter sequence and a contour deformation parameter as well as a mechanical index by calculation performed by virtue of the above-mentioned displacement field function.