Nowadays, one of the key issues in enterprise 2.0 is how to use the innovative knowledge of users and customers systematically and purposely, and also benefit from the knowledge sharing in organizational processes. One effective approach is to make use of an open innovation approach leading to improvement of knowledge flows into the organization. However, to date, specific knowledge management architecture for managing such knowledge flow based on the open innovation approach has not been studied in enterprise 2.0 yet. In this research a new campestral architecture is introduced for knowledge management in enterprise 2.0 that is based on open innovation approach. For this purpose, grounded theory, a qualitative inductive research has been used with emphasis on content analysis of documents and related research studies. The results of content analysis show that the key intersection between knowledge management sharing, enterprise 2.0 and open innovation is knowledge flow management. Therefore, using the characteristics of in-flow and out-flow of knowledge, a conceptual architecture composed of five different layers with seventeen components is proposed. These layers are the logic of business, interface, process and flow of knowledge, infrastructure, and context. In the proposed architecture, each layer has some components that are connected to each other and some of them are connected to the components of other layers as well. The proposed architecture is also compared with two similar architectures in this context as well.