Abstract: The longitudinal hardness,width of heat affected zone,tensile and impact properties of the mobile flash butt welded joint for R260 rail with TB60 profile were studied under different heat input and upsetting distance. The results showed that width of heat affected zone of rail flash welded joint broadens with increase of welding heat input,while the longitudinal hardness tended to be smoother. As upsetting distance increased,differences between the longitudinal hardness values of rail flash butt welded joints first increased and then decreased,while width of heat affected zone basically decreased. And differences of impact and tensile properties under different upsetting distance were not significant.