Abstract: It is pointed out that a cold- formed processing consists of plastic deformation and elastic recovery.We can get residual stress of cold-formed member through adding stress field produced by each course. There are clear differences in distribution of residual stress between the ex isting research and that by the analysis. A vertical residual stress is distributed along thickness of slab, displaying that residual stress is increasing from inside layer to neutral layer. It is pointed out in the ex isting literatures that residual stress is linear distribution that is disadvantageous to stability of structure, because it can clearly reduce effective thickness of slab in bended zone under outer load. Vertical residual tensile stress of outer layer in bended zone is slightly bigger than vertical residual compressive stress of inside layer. The calculated result of cold-formed residual strain is equivalent to that of field measurement.