Abstract: This paper points out that the cold-bending technology is being adopted now in working the arched steel frame of many plastic tents, but this technology leads to the occurence of serious strength mal-formation, namely, the maximum stresses at the sections which negative moment occurs are much larger than the allowable stress, and the maximum stresses at the sections which positive moment occurs are much smaller than the allowable stress. In order to recover this disadvantage, a feasible method which bases on the strain-aging of the steel is adopted. It is easy for operation and cheap forxexpense.