The invention discloses a method for rapidly generating a grait and gravel mixed concrete three-dimensional random aggregate model. A concrete three-dimensional random aggregate model only with grait or gravel is the special circumstance of the grait and gravel mixed concrete three-dimensional random aggregate model. The method comprises the steps that a spherical random aggregate model and a three-dimensional Voronoi diagram with the boundary are combined, and the sphere center of the spherical aggregate is adopted as a control point to generate the three-dimensional Voronoi diagram similarly meeting the aggregate gradation; the peak of each Voronoi diagram is adopted as a control point, a closed spline generated by adopting a subdivision mesh method to represent the shape of the grait aggregate, points are sampled randomly and uniformly on the closed spline curve, and therefore the convex polyhedron is generated to represent the shape of the gravel aggregate. By adopting the parallel mode, volume zooming is performed on each polyhedron aggregate in the three-dimensional Voronoi diagram, and the grait and gravel freely mixed concrete three-dimensional random aggregate model meeting the given gradation is rapidly generated.