Abstract: Interpolation method is one of the most important factors which influence on the accuracy of DEM. After interpolation method is confirmed, interpolation parameters are a primary cause for the accuracy of DEM. However, there are few researches on how interpolation parameters influence interpolation method as well as the interpolation accuracy at last. In this paper, the interpolation parameters in interpolation method of multi log radial basis function is chosen as the research objective and it selects the data of discrete points of five different kinds of physiognomy, uses middle error metrics index and researches the influence of smooth factor, search point and search direction on the interpolation accuracy of DEM.