In the process of core drilling, the artificial deflecting method is an effective means to make up coring for core falling off and bypass obstacles while drilling tool breaking-off and drill bit being buried or burned. For shallow borehole, the inclined section is just under the stepped-diameter position, the stable upper hole wall is convenient for reaming and casing putting, it is advisable to choose the different diameter eccentric wedge for artificial deflecting; for deep borehole, due to the unchangeablehole diameter and hard rocks in deflecting section, the same diameter eccentric wedge is the proper selection for artificial deflecting; for deep borehole with low-hardness rocks in deflecting section, such as coal seam in coal measure strata and mudstone, etc., the same diameter natural deflecting is optimum. When choosing eccentric wedge, the rational determination of its length, deflection angle degree and the diameter of deviation groove, as well as proper operation are the key points; for the same diameter natural deflecting, the determination of the cement slurry filling section, solidification strength of cement slurry and drilling parameters are the key factors.