Optical Doppler tomography (ODT) is a high-resolved and non-invasive biomedical imaging technique,which can obtain tissue structure and blood flow velocity at the same time.A novel phase-resolved ODT method to measure three-dimensional vector velocity is presented.After inserting the designed narrowband phase plate between the collimator and focusing lens of the sample arm,three different phase retardations are formed.By calculating the Doppler shift and the Doppler bandwidth relative to the three phase retardations,three-dimensional vector velocity distribution of the solution inside the capillary is obtained.Several experiments of polystyrene solution with different angle setup and variational flow velocity are conducted,and the results demonstrate the feasibility of this method to measure three-dimensional vector velocity.