Automatic blood vessel analysis plays an important role in computer-aided diagnosis of the vessels. In the blood vessel analysis system, extraction and navigation of vessels are two crucial components, and fast extraction and automatic navigation algorithms attract more and more attention. In this paper, to accelerate the extraction of blood vessel, an initial contour algorithm is proposed to produce an initial contour for level-set method. Then, the level-set method is introduced to extract the vessel more precisely. Finally, the navigation of the extracted blood vessel is realized based on a 3D texture volume rendering algorithm based on graphics processing unit (GPU). The experimental results illustrate the effectiveness of the proposed vessel extraction and navigation scheme.