Abstract: A simplified equation system in σ-coordinate system is obtained by scale analysis for horizontal scale, L~103km. The mountain effect on the wind field in vorticity equation is equivalent to a fixed cyclonic center, but on temperature field in thermodynamic equation, it is equivalent to a fixed high temperature center. In order to describe these effects, the concepts of the topographic equivalent vorticity and the topographic equivalent temprature are introduced. The large scale atmospheric motion under the influence of topographic is also divided into two parts :the adverting change and adjusting change. Each of these parts and their interaction are discussed. Under the condition of the mean and vertical shear westerly current over a mountain, the ageostrophic wind or non-thermal wind may be produced by the adverting process then the vertical motion is caused by the internal adjusting process. But in this case this vertical motion is opposed to that forced directly by boundary condition. however, under some special cases the vextical motion caused by the internal adjusting process and directly by boundary condition may have same direction. These properties is very important to estimate the vertical motion in the weather forcasting.