Gradient Vector Flow (GVF) snake is one kind of active contours - curves that can move within images to find the boundaries of objects. 3D active contours are also known as deformable models. GVF snake begins with calculating the GVF force field over the image domain, which will force the snake into concave regions of original images. Since the calculation of GVF force field usually takes a long time, in this project we implement the GVF algorithm with GPU, which will accelerate the algorithm to a great extent.