Abstract: Concept and rolling technique of flying gauge change for tandem cold rolling are explained. The stretch elongation of strip caused by tension between the stands was investigated during tandem cold rolling. Deformation differential equation and tension differential equation of flying gauge change were established by theoretical derivation according to stress and deformation distribution in the strip during flying gauge change of tandem cold rolling. The influencing factors of flying gauge change were discussed. It is found that tension differential equation of stable rolling is the special case of tension differential equation of flying gauge change during tandem cold rolling.