Abstract: A set of hydrostatic atmospheric thermo-dynamic equations and diffusion equation are solved numerically to simulate the flow,temperature and conceniration fields over Fenhe valley,Shanxi Province.The results are compared with the data observed in a tracer experiment carried out in Spring of 1984.The concentration distributions are calculated by three approaches:ordinary numerical grids model,nested grids model and Gaussian model.The comparison shows that the nested了grids model gives better results and heeds pnly a little more computer time