B2B and long running B2C process is a complex business process that contains a set of services, state and transaction management, and involves notification of various events occurring during the execution of a process. Business processes are driven by events and each process should be capable to handle the dynamic nature of enterprise and business partners like change in the strategies, policies and exception handling. Execution of a business process at regional or national scale involves diversity in products, terminology and processes involved to carry out a complete business activity. Complete execution of a process requires dynamic composition of distributed services based on events. Heterogeneity, dynamic nature and lack of knowledge among business partners demand a scalable architecture, which can provide seamless interoperable integration of distributed heterogeneous services and automation of business processes with the management of state and transaction, notification of various events, and execution and monitoring of a process. In this paper, we have proposed Semantic based Service-Oriented Grid Architecture to demonstrate how semantics can be employed in SOA to deliver common vocabulary, knowledge, and automation of a business process and how grid middleware can be used to provide state, transaction, notification, scalability, and execution and monitoring of business processes.