Abstract: Selecting kernel function in fitting region vertical deformation field using multi-surface function is an important aspect. Four kernel functions are compared in fitting vertical deformation field of three different regions in this paper, and the best kernel function is selected by the external accuracy and the contour map. Tapered surface function is a good kernel function with a strong adaptability by comparison, and it can well fit the rise and fall of region vertical deformation field. Therefore it has some practical values.