Abstract: In view of limitations of inconvenient information read and big drilling engineering quantity existed in traditional advanced prediction method for blind fault, a prediction method of blind fault based on cross-strata drainage boreholes was put forward, the basic principle of the method was discussed based on the fault characteristics, fault diagnosis methods and steps were expounded by use of the least square principle and Matlab drawing function, and the feasibility of the proposed method was verified by an example. The paper provides a new thought and method for mine advanced geological forecast.