The construction industry has worked towards embracing Building Information Model (BIM) innovations for improving the efficiency, accuracy and reliability nowadays. However, the implementation of BIM in building Operations & Maintenance (O & M) is still limited. Previous research only focused on identifying influential factors for the promotion of BIM use in building O &M without considering the systematic manner and the dynamic nature of technology evolution process. This study thus aims to establish an analytical activity system model (ASM) using the activity theory to analyze the BIM use in building O &M in a systematic and dynamic way. The ASMs (traditional and evolutionary) of two different statuses (i.e., without and with BIM-assisted O & M) and the corresponding evolution processes were established based on the critical process models with actors and activities identified in the 1st round interviews with 14 experts. Then, the contradictions as the drivers of evolution in the ASM from the traditional one to the evolutionary BIM-assisted O &M have been examined based on the 2nd round interviews involving the 14 experts and 32 questionnaire surveys. An ASM based driver model of evolution for the BIM-assisted O &M is finally constructed. 26 innovation-oriented internal drivers and six demand-oriented external drivers have been identified, and 21 recommended actions, with the context of social, political and technical influences, have been proposed correspondingly to enhance the identified drivers to achieve BIM-assisted O & M. These results provide a map for O &M practitioners, policy makers and researchers to promote the implementation of BIM in O & M, and are beneficial to the delivery of BIM in building O&M.