A 28-code gear classification and coding system based on the similarity principle of the Group Technology is set up and key technical characteristics of gear products are obtained. Then the geometrically and technically similar part families are clustered through analyzing the results of gear classification and coding, which lead to the formation of gear product standards. Through combining the core features of gear products with rolling bearing identification code sequence,a 11-product-identification-code system is designed and implemented in one special gear manufacturer enterprise.By employing Visual Basic6.0 and SQL Server2000,a Computer Aided Gear Classification and Coding System oriented to Client/Server was developed and exemplified by one specific case. Application results show that the system effectively groups gear products and efficiently categorize the technical characteristics of those having the same classification code into narrower classes,which propell the standardization of gear design and its production.The situation in which various gears are produced in small batches respectively will be improved by large batch production and finally the professional model of mass-customization production will be realized.