The invention belongs to the technical field of computer images, and is applied to a three-dimensional reconstruction method. The method comprises the steps of (1) scanning data, and constructing a cube; (2) calculating a threshold value, constructing a lookup table in three classes, and packaging the lookup table in a protocol mapping table; (3) calculating a gradient; (4) obtaining an intersection edge through a multi-thread parallel method to look up the improved table; (5) calculating coordinates and normal vectors; (6) looking up an improved and expanded triangular plate index table, anddetermining a combination mode; (7) forming a contour surface by triangular plates. The three types of lookup tables correspond to three types of processing functions through a protocol mapping tableidea, the reconstruction speed is greatly increased through function pointer calling and a multi-thread parallel algorithm, and the integrity and timeliness of reconstruction are ensured. The method can be widely applied to various fields of image three-dimensional reconstruction.