Abstract: On the basis of the finite element/Lagrange dynamic model for flexible manipulators,a high accuracy dynamic model for one-link flexible manipulators is given in this paper.The researches for increase of the modelaccuracy are made by two means.First we utilize the concept of extension finite element for deriving optimalshape functions²,by which we get the model accuracy increased without too much additional computation compared to that in1.Then we quote some,conclusions in structure dynamics to take the effect of structure viscous damping into account.Finally we employ the high accuracy model to investigate the effect ofstructure flexibility on performance of force-feedback control systems of one-link manipulators.