Based on the principles of area conservation,a functional relationship of a fault and the morphology of its hanging wall in the section is proposed for extensional listric normal faults. It presumes that the beds in the hanging wall are deformed by simple shearing,while the foot wall on the whole remains unchanged. The shearing direction of the hanging wall is random,which plays an important role in the faults and stratigraphic morphology predicted. The method is programmed with FORTRAN 77 on 386 microcomputer. The extent pattern of listric normal faults could be output directly and rapidly,by inputting arbitrarily the initial fault displacements and simple shear angles.