ing at the problems that non-rigid registration of layered B-spline exists local extremum and the level set segmentation method is not suitable for noisy image segmentation, a joint segmentation and registration of medical image based on locally updated hierarchical B-spline bidirectional transformation and level set method is proposed. The proposed method adds a registration transformation to the segmentation algorithm, and the structure information of image segmentation is incorporated into the registration. The B-spline level set function is used to smooth the transformed and segmented image, and a two-way transformation is introduced in the registration to improve the accuracy and smoothness of the registration. Based on the level set method, the bi-directional layered B-spline transform is introduced to construct the joint energy functional of segmentation and registration, and the gradient descent method is used to minimize the energy functional to optimize the objective function. Experimental results show that the Dice metric is always above 99% and the mean square error is reduced by 30% compared with the single image segmentation method. The proposed method improves the registration accuracy and has better robustness in noise image segmentation.