In order to study the fire resistance of restrained high strength Q460 steel beam，the residual stresses were introduced to analyze the fire resistance of restrained steel beam. The method was validated by experiment conductedon restrained mild steel beams. Fire resistance of restrained high strength Q460 steel beams was analyzed and compared with that of restrained mild Q345 steel beams and parameters affecting the fire resistance of restrained high strength Q460 steel beams were studied The parameters included load ratio，residual stress，stiffness of axial restraint，stiffness of rotational restraint and fire exposure mode. The results showed that the innovative method proposedwas accurate and reliable; the fire resistance of restrained high strength Q460 steel beam was much better than mild steel beam and the former. Load ratio，stiffness of axial restraint，stiffness of rotational restraint and fire exposure mode had significant influence on fire resistance of restrained Q460 steel beam.