Digital geological map is a spatial database with data as its basis an d with GIS techniques as its platform .In order effectively to exchange, to mana ge and to share digitalized geological maps, it is imperative to develop the geo logical map data models. As an example on investigation of the geological map data model by U S G S ,th e paper defined a relational data model which could be implemented on a modern G IS and described the tools and methods which would be needed to carry out the re lational data model .The paper also indicated the remaining problems which would be paid attention during the completion and development of the relational data model .