In the context of a network of enterprises, the competitive advantage of each enterprise depends greatly on the ability to use network architectures to collaborate efficiently in business services. The paper introduces a conceptual framework, called the CBSM (Collaborative Business Service Modelling) framework, which provides an intellectual foundation for understanding thoroughly and modelling effectively collaborative business services. The paper begins by presenting the necessity for and principles of the conceptual framework. Then it presents the architecture of the CBSM framework that consists of three different levels: the service level for service operation, the service system level for service creation, and the service value creation network level for service proposal. The paper continues with a discussion and review of the relevant literature, followed by the conclusion and suggestions for further research.