To solve the computer description of Fault tree model, a new method based on the extended fault tree nodes' nonlinear linked lists representation is put forward according to the analysis of the fault tree mathematical model and inference mechanism. With this method, the process of fault tree diagnosis can be fully represented of this method and the process of fault tree diagnosis inference mechanism can be optimized. So the whole system will get a certain self-learning and adaptive ability. It is a good solution to the fault tree model description and computer storage problems, and opens up new avenues for the expert system knowledge acquisition.