Abstract: China's geochemical mapping has maintained its leading position in the world for decades,thus stimulating the development of the concept and methodology of geochemical blocks.The geochemical family tree diagram drawn based on the concept of geochemical blocks and using a certain coding system is a powerful tool for studying the internal structure of geochemical blocks and tracing the progressive concentration of a particular metallic element to form ore deposits.Through the family tree diagram we can find the affinity between blocks of different orders and study their temporal-spatial distribution patterns,and,by using the family tree diagram,combined the information of ore deposits that have been found,we can prediction the distribution and reserves of the potential deposits and thus can guide mineral exploration.The coding and construction of the family tree diagram have been conducted manually in the past.It is a very tedious work.In this paper,the authors have developed a new family tree coding system and a software for automatic coding and construction of the family tree diagram,thus solving the long-standing problem that the family tree diagram cannot be drawn automatically.