Ma, L.H. Li, M. Sheng, W.F. Tang, S. Wang, J.Y. JACoW Publishing Geneva, Switzerland The main function of the generic mirror chamber system in HEPS is to support, adjust the pose and provide the ultra-high vacuum environment of the optical elements in the beamline. Its pose adjustment requires micrometer or submicroradian level repetitive positioning accuracy and adjustment resolution. The white beam bending mirror chamber in the generic mirror chamber system of the Hard X-ray Nanoprobe Multimodal Imaging Beamline(B2) is taken as an example, to discuss the design of its pose adjustment mechanism. It needs to achieve 5-DOF for pose adjustment function. This paper proposes using a multi-layer marble structure and a combination of multiple motion mechanisms to achieve this function. The motor and screw-nut pair drive sliders can achieve 2-DOF adjustment. The motor and screw-nut pair drive two wedge-shaped blocks can achieve 2-DOF adjustment. The motor and straight circular flexible hinge drive a disc-type flexible hinge can achieve one angle adjustment. Finally, through series of numerical calculations, finite element simulations and physical experiments, it is demonstrated that the design indexes meet the requirements, thus verifying the feasibility of the scheme.