Abstract: This paper discusses the use of the digital geological survey system in the supplemental survey project of the regional geological survey of 1∶250000 Bulitai Sheet and Siziwang Qi Sheet. Based on the actual conditions of the supplemental survey, the PRB process, which is the core of digital mapping, is divided into six stages. The paper stresses the importance of using previous information in the supplemental geological survey and presents some problems in the collection and input of previous data. In addition, it introduces the processes of collection along the field geological traverses and geological sections and data compilation and analysis and indicates the problems and methods for solving these problems in that process.