The force testing central support is an important part of the model supporting system in a transonic & supersonic wind tunnel,the performance of which is qualified or not would directly affect the control of model attitude angel during wind tunnel tests.First,aiming at the problem that the roll angle backlash is oversized during force tests,the self-locking dual lead cylindrical worm transmission is applied to the force testing central support to solve this problem.Meanwhile,considering that the aerodynamic load is heavy,the slider and the bulging joining sleeve are both used to share the load.Then,the static structural strength of the worm transmission are checked,and at the same time,the finite element analysis is carried out to study the stress and deformation both in the sustaining body and the chief axis.Finally,the calibration model tests for the new force testing central support in comparison with the former one are conducted.Results indicate that the structural design is reasonable,the data presented a good correlation,and the design of the new force testing support is successful for wind tunnel tests.