Yu, H.H. Li, M. Li, Y. Liao, R.Y. Sheng, W.F. Tang, S. Xu, R.Z. JACoW Publishing Geneva, Switzerland Nano-KB/AKB mirrors are used to focus spot size to the nanometer level in main performance beamlines at HEPS, including the Hard X-ray Nanoprobe Multimodal Imaging Beamline(NAMI Beamline), the Hard X-ray Coherent Scattering Beamline(HXCS Beamline), and X-ray Absorption Spectroscopy Beamline(XAS Beamline), etc. For the typical Nano-KB/AKB mirrors mechanical system, a common design of the mounting and clamping mechanisms and the adjustment mechanisms is presented. There are also the key components of the Nano-KB/AKB mirrors mechanical system. Currently, through the design and optimisation of the mechanical structure and the corresponding finite element analysis(FEA), the first Nano-KB mirrors mechanical system at HEPS has been fabricated, and the large travel range, high resolution and high stability adjustments mechanisms are achieved, the slope error of the Nano-KB mirrors is well ensured simultaneously, and the test results are consistent with the design.