Internal force of a concrete block should be calculated when reinforcing of the block is calculated according to concrete code. However, because some concrete blocks are irregular, generally they are calculated by FEM software. When complicated solid structure is analyzed by ANSYS software, the internal forces of solid elements can’t be achieved directly, so ANSYS should be developed secondly. This paper introduces the calculation theories which transfer stresses to internal forces and which are applied to the internal forces calculation of solid elements in ANSYS secondary development. This paper combines an actual engineering, the moment diagrams and torque diagrams are achieved, and the results indicate that the internal force progress developed is of applicability and commonality for solid element, therefore the progress can be applied to ANSYS for the analysis of harbor engineering.