A CT three-dimensional reconstruction method and system. The method comprises: sending to at least two lower-level computers a two-dimensional projection image obtained by performing computed tomography (CT) with at least two rotation angles of an X ray source (210) (110) controlling each of the lower-level computers to compute a projection matrix for each pixel point in the two-dimensional projection image received thereby, and saving the projection matrix to respective internal storages of each of the lower-level computers (120) controlling each of the lower-level computers to compute, on the basis of the projection matrix and a current iteration state of three-dimensional volume data to be reconstructed, an iteration decay component and returning the iteration decay component (130) updating, on the basis of the iteration decay component, the current iteration state (140) determining whether an iteration termination condition is met (150), if the iteration termination condition is not met, then returning to control each of the lower-level computers for the projection matrix and the current iteration state to compute the iteration decay component and return the same until the preset iteration termination condition is met and if the iteration termination condition is met, then using the current iteration state after iteration terminates as a CT three-dimensional reproduction result (160).La présente invention concerne un procédé et un système de reconstruction tridimensionnelle de tomodensitométrie. Le procédé consiste à : envoyer à au moins deux ordinateurs de niveau inférieur une image de projection bidimensionnelle obtenue par la réalisation dune tomodensitométrie (CT) avec au moins deux angles de rotation dune source de rayons X (210) (110) commander chacun des ordinateurs de niveau inférieur pour calculer une matrice de projection pour chaque point de pixel dans limage de projection bidimensionnelle reçue, et sauvegarder la matrice de projection à des stockage