By use of concepts of pointer and derived type in FORTRAN90

a linked list which carried out a dynamic memory allocation for global stiffness matrix and enforced its flexibility is made. Consequently

it avoids lots of shortcomings in the array memory and the old method of forming the global stiffness matrix. This method can be very easy in data processing of the global stiffness matrix such as insert

delete etc. and be invariability in the structure of the array. At the same time the method can save more EMS memory than the common half-band memory. So the method is especially suitable to analyzing the extraction and support with the geotechnical engineering in the 3-D FEM and can enormously reduce times of solving equations.