Abstract
Software as a Service (SaaS) has become a popular software service mode. Tenants can access SaaS application via the web and essentially rent the application from SaaS provider. This paper proposes a flexible, multi-tenant oriented business process customization system to resolve the problem caused by orchestrating SaaS business process base on BPEL. The system includes kernel framework, resource layer and execution environment. It enables multi-tenant to customize services and processes during defining. When deploying process definition into process engine, the system is also able to verify the correctness of process logic. At the runtime of process, the system can dynamically modify or substitute the service or handle abnormal situation automatically according to the rules provided by tenant or system.