The exited popular ways of evacuation simulation can't satisfy us in the computational efficiency and the calculation accuracy at the same time. In order to get acceptable efficiency and accuracy, we applied the related concept of statistical physics to the specific circumstances of evacuation and built an evacuation model based on Boltzmann Distribution. We also came up with the exit attraction function and direction judging principles to depict people's exit choosing and obstacles avoiding behaviors. At last, we proved our model is applicable and reasonable by comparing the classical models with ours.