This paper analysed the atmospheric pressure, air temperature, humidity, wind field and rainfall in loess plateau, and the relationship between topography and climate has been discussed.The results obtained has showed that (1). the topography has a great influence upon atmospheric pressure field whether in winter or summer. Furthermore, the character of this influence and the direction of rife-wind are closely interconnected, (2) The rife-wind is suited to the pressure systems, and they have closely relation to rainfall, (3) The Baiyu Mountains is an important climateline.