The digital deposit model is meant to transfer the deposit features described in traditional geological terms into the data and code that can be understood by computer and put AI knowledge and rules into computer so that the computer can reasoning automatically and assist geologists, exploration companies to make decisions. The research is based on the achievement of the predecessors, combined with advanced theory and experience from domestic and abroad .The paper set forth the principle and method of digital copper deposit model and some key techniques in the implementation of the system. The knowledge and rules were built with the help of the copper geologists, who provided the parameters related to the reasoning such as pre probabilities, which were handled with statistics method. The results presented in this paper reflect preliminary achievement of the project supported by Chinese High-Technology Research and Development (863) Program.