Abstract: In brain white matter fiber tractography,diffusion tensor magnetic resonance imaging(DT-MRI) can be used to reconstruct the three dimensional structures of the white matter fibers noninvasively.The commonly used tracking method is usually based on the local diffusion information and insufficient to consider the geometrical structure of the whole fiber bundle.Therefore,a novel method of fiber tracking using Bayesian decision stochastic model is proposed.In this method,from the diffusion tensor directions of the current voxel and the structure information of the current fiber segment,the probability distributions of the tracking directions of the next voxel is estimated using Bayesian decision theory.Then,according to the probability distributions,the fiber bundle is sampled and the 3D image of its structure is reconstructed.By the method,imaging simulations using a synthetic diffusion tensor dataset and imaging experiments using an in vivo brain DT-MRI dataset have been done.The results of the simulations and experiments demonstrate that using the method proposed,brain white matter fiber can be reconstructed properly as expected,more reliably and repeatedly compared with the common methods.