Abstract: The dynamical microstructure evolution behavior of Q235 low carbon steel at high temperature was systematically investigated through physical simulated tests carried out on a Gleeble 2000 machine. The experimental results showed that hot working parameters such as forming temperature and strain rate affected the dynamical micro-structure evolution behavior of Q235 steel to a great extent. At a given temperature, dynamical recrystalization could be postponed with the increasing of strain rate; meanwhile, at a lower strain rate, this phenomenon could occur with the decreasing of temperature. The quantitative metallurgical technique and the linear/non-linear regression analysis were used to construct an Arrhenius-type phenomenological constitutive relationship and a Yada-type kinetically microstructure equation of Q235 steel at high temperature, which were coupled into the finite element software of Autoforge 3.1. The results of numerical simulation showed that the phenomenological constitutive relationship and microstructure evolution equation depicted the dynamical microstructure evolution behavior of Q235 low carbon steel at high temperature very well.