An increasingly important requirement for software systems is the capability to evolve dynamically according to the changes of computing environment and users’ need during runtime. In this paper, a dynamic software architecture oriented approach is proposed to support online evolution. Notably, architecture information is reified as explicit and manipulable entities to organize a runtime architecture meta-model, which is causally connected to software implementation and specification. By using reflection, the evolved architecture meta-model modifies running system, and updates specification simultaneously. The well-defined architecture meta-model supervises all evolutionary behaviors to ensure system consistency, integrity, and evolution traceability. Based on this model, a visualized integrated development platform entitled Artemis-ARC is also successfully implemented. It supports component and service design, development and assembly, especially dynamic evolution. Furthermore, a simple application case is developed with Artemis-ARC to illustrate the effect of online evolution.