Abstract: Based on the memory cutting method with double demo knifes as well as the high labor intensity features of the cutting parameter sampling operation, th e paper analyze the mutual relationship between the operation status parameters of the coal shearer and the seam parameters and provided the memory cutting metho d with a single demo knife. The mathematic relationships of the geometric parameters, operation position and attitude parameters of the coal shearer as well as the sea m parameter and cutting drum location were established.The memory cutting digitalized model of the face roof under the single demo knife was provided.With the multi cycle digital simulation of the cutting traces for the coal shearer, there was a good fitting between the results and the sample traces, which could provide the theoretical basis for the programmed control system design of the single demo knife memory cutting for the coal shearer.