With the application of information technologies such as 5G and artificial intelligence in transportation engineering, autonomous driving system (ADS) has developed rapidly. As the basis of system planning and designing, multi-dimensional architecture is an essential part of the top-level design of ADS. According to the users’ demands, we divide the user services in ADS and construct the system's functional, logical, and physical architecture in the study. A multi-dimensional architecture mapping relationship of ADS is designed, and a corresponding optimization method is proposed. By calculating the correlation matrix between the functional elements and selecting different thresholds to intercept the correlation matrix elements, the optimal multi-dimensional architecture mapping relationship structure is obtained. The results obtained in this study provide suggestions for the optimal mapping relationship design in ADS.