Gas-surface interaction models in direct simulation Monte Carlo (DSMC) method for hypersonic rarefied flow is studied based on unstructured grids. A wall boundary condition based on radiative equilibrium is developed, which can overcome the defects of isothermal boundary condition and provide more precise wall temperature distribution during numercial simulations. The Maxwell reflection boundary model, coupled with diffuse reflection and specular reflection,is applied. Numerical results of a blunt body configuration are obtained. Test cases show that the developed models can improve the sensitivity of the temperature variation in afterbody field, and the sensitivity decreases with the simulated flying altitude increases.