Abstract. Online learning is a learning way to use online education platform for learners. It could let the learners start learning at anytime from anywhere by removing the traditional education's time and space limit. As the online learning style becomes more and more popular, its main base environment has gradually shown problems such as platform-independent platform's architecture, regional education information resources distribution model, information island issue between the learning platforms and other issues. The emerging of cloud computing makes it possible to solve these problems effectively. Cloud computing is composed of a large number of different computer resources, through the distributed systems and virtualization technologies such as software and hardware virtualization, all resources could make a unified resource pool, then allocate computation, storage and other services to the customers by demand. At present, mature cloud computing platforms usually have over one million cluster servers, and can provide powerful computing capacity and huge amounts of storage space. This paper discusses building of a unified, open online learning system based on features of cloud computing service, and existing Google cloud computing platform -Google App Engine, aims to get rid of the defects of traditional online learning platform.