Abstract: In this paper, the bar-system structure on elastic supports is taken as a "Carrier", in order to illustrate the fundamental conceptions and practical applications of the boundary value method in structural analysis. The boundary value method is a gradually formed general method in strucural analysis, studied by the author for about 20 years. It has unified theproblems of stresses and displacements analysis of bar and plate-system strucures in a canonical equation called "The matrix boundary value equation", to make the solution of problems comprehensively perfect in theory and convenent in practice, saving a lot of storage in computer, starting a new way to use microcomputer for solving the complicated problems in structures.