Provided is a geometric model establishment method based on medical image data, including: a step of reading medical image data； a step of defining a tissue type by a conversion relationship between the medical image data and the tissue type； a step of deciding the number of tissue clusters； a step of defining a tissue density by a conversion relationship between the medical image data and the density； a step of establishing 3D encoding matrix with information about the tissue and the density； and a step of generating a geometric model. According to a conversion relationship between medical image data and a tissue type, the number of tissue clusters can be determined according to actual requirements, so that the tissue type, the element composition and the density are provided more accurately, and an established geometric model is better matched to the real situation reflected by the medical image data.
