The technology of drilling with casing is widely used in the field of oil and gas drilling as the feature of hole wall protection， sticking and leakage prevention， and efficiency enhancement of casing operation. However because of the complex condition of formations in coal mines and the limitations of underground space and existing drilling equipment， this technology is not applicated on large-scale to solve the prolem in coal mine i.e. casing operation difficulty， low operating efficiency and so on. Focusing on these problems，taking the Zhaogu Second Mine as an example，based on the analysis of the reason for casing difficulties in complex broken strata， this paper proposed the technology of drilling with casing driven at the bottom borehole，developed the bottom transmitting torque mechanism and made industrial tests in Zhaogu Second Mine. The results showed that the problem of casing non-rotation， no slag discharge and being stuck under conventional casing process were solved by this technology， moreover， the problem of low casing efficiency and easy to form waste boreholes were also solved. This technology has greater advantages in the application of drilling across complex broken strata.