Abstract: Weathering-suspected crystals will be weathered and lose crystalline solvent after depend from the mother liquor, and result in the structural collapse and turn into powder, thus to test weathering-suspected crystals is very difficult. Making use of the principle that weathering-suspected crystals are usually relatively stable at low temperatures, we developed a special system to help selecting and sampling in low- temperature environment, so that the diffraction data for weathering-suspected crystals cab be obtained. The development of this system provides a strong technical guarantee for the testing of the structure weathering-suspected crystals in related research. It is an important technological innovation in the functional development of single crystal diffractometers.