Warm deformation behavior of the Fe-6.5wt.％Si alloy was studied by isothermal compression in the temperature range of 300-700℃.The results show that the influence of the ordered phases on the flow stress gradually weakens with increasing deformation temperature.The flow stress of the face-cooled sample with the high degree of order at 300℃ is higher than that of the quenched sample with the low degree of order,and the flow stresses of both samples are nearly the same at 500-700℃.The hardness difference between two samples deformed at 500℃ gradually decreases with increasing strain,accompanying with a reduction in hardness of the face-cooled sample,which indicates a work-softening behavior.The analyses of dislocation configurations and ordered structure suggest that the dynamic recovery and deformation-induced disorder result in the work-softening behavior.An appropriate deformation temperature window for improving the formability of the Fe-6.5wt.％Si alloy is about 500-600℃.