As the preliminary step of the fault injection, the way of fault sample selection has a significant influence on the testing  result. In order to promote the efficiency as well as to guarantee the correctness, a theoretical framework for fault sample  selection for telescope drive control system based on the SDG (Sighed Digraph) modeling and the importance of nodes in  graph theory is proposed in this study. Firstly, the SDG model is developed qualitatively according to the mathematical  equations of control loops utilizing classic control methods. Secondly, the compatible pathways are introduced which can  depict the fault propagation completely and the importance of the model nodes based on destroying degrees relative to the  components of the drive control system are introduced. Finally, a procedure of fault sample selection method is proposed  to show an efficient result which only needs a few of fault samples and data information.