The finite element simulation model of transient temperature field of drilling rig hydraulic brake discs is built up. The thermal- mechanical coupling simulation and calculation of model is carried out by using ABAQUS. The influence of parameters changing on distribution of temperature field and stress field is studied specially. The distribution of temperature field,stress field,as well as related conclusions are consistent when the parameters of convective heat transfer coefficient,braking time,thermal expansion coefficient,thermal conductivity,friction coefficient are changed only but braking conditions. For the brake discs,reduction in its holistic temperature and stress could be achieved by increasing the convective heat transfer coefficient and the thermal conductivity,reducing the thermal expansion coefficient and the friction coefficient. A theoretical guidance for optimization design of brake disc is provided by the conclusion of simulation analysis.