Diao, Q.S. Hong, Z. Lian, H. JACoW Publishing Geneva, Switzerland Crystal monochromator is one of the core optical components of X-ray transmission, and its internal residual stress and surface roughness directly affect the quality of X-ray. With the development of synchrotron radiation sources, better uniformity and stability of X-ray beams are required. The beam intensity and position stability of conventional double crystal monochromator is affected by clamping and cooling mechanism. Although channel-cutl monochromator can meet the requirements of X-ray stability, but the polishing of the inside diffraction surface is a really challenge. It is difficult to promote implementation because the only guiding principle of empirical and lack of scientific data support system. So it is imperative to develop crystal monochromator with good beam quality and high stability. This project intends to combine the crystal polishing technology and optical surface shape measuring instrument to carry out research on micro-radian level high-precision crystal orientation and massive crystal silicon bonding technology, and complete a group of stress-free plane crystals with ultra-high surface shape accuracy within 1 ¿rad orientation error.