Abstract: Post-earthquake transitional housings which built in Chenjiaba District, Beichuan County, Sichuan Province aided by Qingdao are light steel structure assembled housings. For which cold-formed thin-wall steel structure system is used and jointless plates with direct welding connection are also used between truss members and are characterised by simple production, light weight, easy installation, convenient disassembly and reuse, short construction period, reliable structure force and strong seismic ability. It is analysed bearing capacity of truss members and the distribution and effect of the secondary stresses. The results show that transitional housing placements structure has adequate security. The adverse effects of secondary stress due to node geometric flaw to steel truss without node plate connections should be considered when internal force is analysed.