Abstract: The method of dealing with the hinge for directional supports has been put forward while making use of the changing-hinge's analysis method to determine the unattached unknown node linear displacement of displacement method.It is proved that the linear displacement of linking bar supports and directional support paralleled the bar axis should not regard the unattached unknown node linear displacement of displacement method,and the linear displacement of linking bar supports and directional support un-paralleled the bar axis should regard the unattached unknown node linear displacement.The simple calculation formulas of determining the unattached unknown node linear displacement by the changing-hinge's analysis method have been summarized.The changing-hinge's analysis method has not confined to the boundary condition in this paper,the correctness of the formulas has been validated by some examples.