Abstract: Today,the numerical simulation of regional climate is an important problem of climate research. The CSU-RAMS mesoscale numerical model was transformed suitably into a "reginal climate model",and some numerical simulation work was performed. The results show: It is significant that a limited-area meso-scale model nested to a coarse GCM applies to regional climate smulation. It would improve GCM results. This method is valid for understanding regional climate change.