Abstract: At present, there are more and more wells with unconventional wellbore such as 9.5 inch in the exploratory well operation in Bohai Oilfield. In this type of wells, the same open hole runs through multiple strata, and the reservoir compaction degree and lithology characteristics of different strata are different, which brings challenges to the coring operation of cable wellbore. In order to improve the operation efficiency of cable borehole coring of unconventional wellbores, improve the coring recovery rate and sidewall coring quality. Through studying the two operation methods of conventional borehole coring and rotary borehole coring, this paper analyze and refine the selection of operation methods and operation techniques in combination with the principle of borehole coring. While, it is concluded that the appropriate borehole coring method and the key point control scheme for different borehole coring methods should be selected according to the well conditions and the compaction situation of the target layers. This method greatly improves the recovery rate and operation efficiency of cable borehole coring in unconventional wellbores, and also ensures the original stratigraphic properties of the core. It provides physical support for geological exploration, reservoir research and reserve declaration, with very high feasibility, wide coverage, great application and promotion value, and also provides a new direction for the improvement and research of subsequent cable borehole instruments.