With the rapid development of computer technology, surgical training, and the digitalized teaching of human body morphology are gaining prominence in medical education. Accurate, true organ models are essential digital material for these computer-assisted systems. However, no direct three-dimensional (3D) true organ model acquisition method currently exists. Thus, the direct extraction of the interested organ models based on the existing Virtual Human Project (VHP) image set is urgently needed. In this paper, a closed-form solution-based volume matting method is proposed. Using a small quantity of graffiti in the foreground and background, target 3D regions can be extracted by closed-form solution computing. The upper triangular storage strategy and the preconditioned conjugate-gradient (PCG) method also promote robustness. Four image data sets (2 virtual human male and 2 virtual human female) from the United States National Library of Medicine (including brain slices, eye slices, lung slices, heart slices, liver slices, kidney slices, spine slices, arm slices, vastus slices, and foot slices) were selected to extract the 3D volume organ models. The experimental results show that the extracted 3D organs were acceptable and satisfactory. This method may provide technical support for medical and other scientific research fields.