Based on analysis of rigidity and drift error for a Dynamically Tuned Gyro(DTG),a cross model including an inner and an outer flexible hinges was established.The influence of the relative position of two flexible connector hinges on cross hinge model was given by analyzing the model with the Pseudo-rigid-body Model.It has been found out that the rigidity variety of the model requires a high assembly accuracy of whole gyro in coaxiality and orthogonality,which should supervise the whole assemblage and debugging technique.