To solve the context describe of quality of Web service in ubiquitous network environment, service comp- osition-oriented complex context ontology model-OWL_S_QoS+ is proposed, which includes user context ontology and service context ontology. User context ontology describe user's environment, user's resource, user's requirements and user's group and so on, these information affects the running of Web service. Web service context ontology is defined Based on OWL_S, which added the running environment requirements of Web service in client and server and the QoS description method with uncertainty.