Coupled six-degree-of-freedom(6-DOF) trajectory predictions and the technique of dynamic mesh, numerical investigation is conducted to analyze the effects of the interior store separation from one side of the blended-wing-body (BWB) underwater glider via computational fluid dynamics based on unstructured meshes.Hydrodynamic performance of the glider affected by the store releasing is demonstrated.The surrounding flow structure changes with the separation courses.Finally, the trajectories of the glider at different attack angles affected by the releasing are shown.Guideline to make sure the security of internal store separation is proposed according to the results.