With the increasing demand of combining business process management (BPM) with service-oriented architecture (SOA) in the information age, and focusing on the deficiencies of researches in this field currently, such as disjunction between concepts and modeling languages, ignorance of conversion from computing independent model to platform independent model, and difficulty in penetrating multiple views of a whole system, the business process modeling of service-oriented architecture was introduced based on the combination of BPM and SOA. Then by means of distinguishing the concepts of ontology meta-model and notation meta-model, the mapping relationship between two modeling languages was established, including the semantic layer mapping as well as the syntactic layer mapping, and was implemented by two-step-inference taking BPMN and SoaML as specific modeling languages. Finally, the modeling method as well as mapping rules between BPMN and SoaML were applied to a case study in order to prove the feasibility.