The fundamental reason of slip line is that the internal stress of monocrystalline silicon exceeds the bearing capacity (yield strength) of the lattice, which leads to lattice deformation. Because of the different deformation, it is macroscopically manifested as dislocation, stacking fault, slip line and so on. Stress is divided into mechanical stress and thermal stress, and the slip line caused by thermal stress is produced during crystal pulling, which is generally called single crystal slip line. Usually, the crystal is confiscated after pulling, and the temperature drops too fast, which leads to the dislocation of the crystal lattice at the tail of the crystal bar, and then the slip line is produced. The slip line caused by mechanical stress is often caused by the damage of chamfer surface in silicon wafer processing. Because the damage of chamfer surface will cause the slip line after epitaxy, which is also called epitaxial slip line. The general preventive measures of slip line caused by thermal stress are to improve the distribution of thermal field, increase casting speed and control temperature curve. The general preventive measure of epitaxial slip line caused by mechanical stress is to improve the machining level of scarless chamfer surface.