Aiming at the problem of distortion of the output signal of the traditional sixaxis accelerometer, a 12-branched and preloaded sixaxis accelerometer model with parallel mechanism is designed in this paper. By adding subplates on the shell, preloading screws, locking plates, the preload and anti-loose function of all the branches are realized. The results of the virtual test show that the axial forces of the branch are positive pressure after the preload, indicating that the scheme is effective. From the decoupling characteristics, the elastic hinge material is determined to be 65Mn and its minimum diameter is 1.5 mm. By calculating, the maximum stress is 388.31 MPa, and the maximum deformation is 0.009 mm at operating. Finally, the design of the virtual instrument, including data acquisition module and data processing module, provides a software support for the follow-up test of the sensor.