Three R.C. frame structure models were designed with named KJ1, KJ2 and KJ3. Elevated temperature experiments were carried out to KJ1 and KJ2 with concrete crack width 0.2mm and 0.4mm respectively which was taken as the damage index ω caused by earthquake, KJ3 was directly undertaken to elevated temperature experiment. The laws of concrete crack development, axial deformation of frame column and standard heating curves were studied. The law between concrete crack ω and deteriorated performance for concrete frame structure was put forward, which can be a good reference for research on fire resistance performance of R.C. frame structure after earthquake.