Shape formation of post-tensioned and shaped hypar space truss is presented in this paper, the test space truss can be deformed into saddle shape by tensioning positive diagonal bottom layer strand. Nonlinear finite element analysis is applied in shape formation of space truss model. Based on both geometry and material nonlinearity, new FEM refering ‘tube to tube’ contact, is employed. Connector elements are used to simulate the bolt connection of the top joint, and the end of web. The results show that new method is relatively much more accurate than the previous way for the shaped size, and the theoretical values are consistent with experimental ones in stress and internal force distribution trend although the former ones are smaller, for FE model could not consider diagonal lower chord joining the structural system during shape formation.