DevOps (development and operations) methodology, as the integration of agile software development method and lean concept, has aroused great interest and concern in the software industry in recent years. The application value of DevOps has been widely recognized by the whole industry due to its massive advantages, such as the significantly decreased time to production, in-creased reliability and stability. However, currently very limited application cases have been reported while there is almost no large-scale application of DevOps software platform. In this study, we have proposed and built an end-to-end and innovative DevOps platform of the whole process, namely the YunDao platform. The system design of the YunDao platform, mainly including the overall architecture, technical architecture, development architecture and functional architecture, was systematically presented and discussed. This work can be considered as a breakthrough in the field of commercial application of large-scale DevOps platform.