Abstract: The technology of bolt supporting under the condition of tight roof has been successfully used. However, until now the supporting technology of roadway has not been reported when the roadway must be driven along the bottom in the loose thick coal seam. The authors firstly use 3D anchor-cable into this filed. This paper,from the point of view of mechanics, gives an emphasis on the supporting mechanism of 3D anchor-cable, and this kind of experiment has been carried out. Aimed at the unloading technology of the wall of roadway, the supporting problem mentioned above can be solved accordingly. In the application, this technology has produced enormous economic and social effect, so it is of great value to be applied to the similar condition.