In order to extend the capture range of the external force field in the parametric active contour model and to eliminate the effect of the noise on the segmentation with weak edges,this paper proposes a novel parameter active contour model by combining the advantages of the parameter active contour with those of the vector field con-volution.In this model,first,an edge image is obtained through Harris matrix,and the probability of the noise is estimated according to the mean and variance in a local region.Then,the weights of both the parameter active con-tour and the vector field convolution are determined.Finally,a global vector field is achieved.Simulation results of synthetic edge images and medical images indicate that the proposed method can accurately segment objects and can resist noises to a certain degree.