Abstract: The basic definition and the classification methods of the map projection have been introduced in this paper,with focus on discussion about the deformation characteristics of commonly used map projection in oil and gas exploration.It is believed through analysis that Gauss projection and UTM projection are relatively small in deformation length and deformation area,while Mercator projection is relatively large in deformation length and deformation area.Finally,it is pointed out in this paper that it is necessary to make careful consideration when selecting the way of projection during compilation of geological map.