Abstract: There are several key mechanical problems in simulating construction process of structures, such as how to simulate time-variation structures and boundary conditions, and how to take time-dependent material into consideration. This paper reveals the principles of element’s ‘death’, ‘floating’ and ‘birth’ for element birth and death technology mathematically and physically. Another simulation method, namely step-by-step model technology, is also discussed. Using the classic beam element, this paper develops analytic models for construction simulation by means of FORTRAN programming. Moreover, the methods using the above two technologies are compared in this paper. The results demonstrate that both methods can be used to predict the development and variation of internal forces and deformation of steel structures during construction.