Abstract: Scanning electron microscopy( SEM) and nuclear magnetic resonance( NMR) crosslinking density meter were adopted to analyze the structures of rubber pad material for railway vehicle before and after thermal ageing,and changes of mechanical properties and dynamic mechanical properties were studied. The results showed that at 80 ℃,with increasing of the ageing time,the internal structure changes of the materials were not intuitively obvious,crosslinking density increased at first and then decreased,the tensile strength increased at first and then decreased,elongation at break was decreasing,hardness tended to increase,storage modulus gradually increased,and loss factor increased at first and then decreased.