An improved C-V active contour model was presented,with which the image data force in the C-V model is significantly simplified according to the curve evolution theory.The level set function can be initialized to be zero according to the theory analysis.Distinguished from original C-V model,the level set function of the proposed model is Ordinary Differential Equation(ODE).The proposed model not only has the original C-V model's characteristics,such as the ability of detecting inner edge of the object with inner hole,etc,but also has many advantages as follows:anti-noise performance is good;re-initialization is unnecessary,and the efficiency of global segmentation is dramatically improved;the edges far away from the active contours would be seriously suppressed by setting the Dirac function to be one;the implementation does not require any limitation of time step.The method is validated with both synthetic and real images.Experimental results demonstrate the robustness and efficiency of the model.