Interventional treatment becomes increasingly popular since this technique means substantially less trauma for the patient. By using VTK and ITK to build a plan system, the treatment can be high efficiency. VTK is responsible for visualization, while ITK takes care of the image segmentation and registration. By combining VTK and ITK, and using Qt as the user interface, an interventional treatment plan system is built. This system has finished several mainly functions, like DICOM data displaying in multi-planar reformation, manual segmentation, semi-automatic segmentation, surface rendering using marching cubes algorithm, volume rendering using volume ray casting algorithm. Also an interventional treatment plan system has been developed based on the medical inspection.