Abstract: A path planning method for underwater glider is proposed based on local flow field construction. Firstly, the depth-averaged currents from the future profiles are predicted based on the depth-averaged currents from the historical profiles, and their positions are determined as well. Then several depth-averaged currents from the top profiles are taken as the observations, and a local flow field is constructed by the objective analysis technology. Finally, CTS-A^* (constant time surfacing A^*) iterative algorithm is applied to path planning based on the constructed flow field. In the simulation environments, the path planning method is tested in a single flow map and numerous flow maps, and the results are analyzed. The results show that the path planning method can apply to the situations of ordinary ocean currents and strong ocean currents.