Since the long-span steel structure is prone to perform nonlinearity such as yielding rigid body motion under construction loading, construction process analysis was conducted by the Vector Form Intrinsic Finite Element method (VFIFE). Based on the basic theory of the VFIFE, the tensioning cable element was introduced to simulate the tensioning process by adjusting the length of the cable element. In addition, the jack element was used for the unloading analysis of the long-span steel structure. Moreover, the VFIFE based program was developed by the MATLAB, and compared with the conventional method by means of three FE models such as the assembly of cantilever beam, the tension forming of cable truss, and the tensioning construction of long-span truss string structure. To this end, the VFIFE theory and program were verified and validated. The result showed that the assembly, tension forming, and unloading of the long-span steel structures could be reasonably simulated by the VFIFE.