Current IEC 61131-3 programmable logical controllers are facing challenges to provide reliable system as well as exceptional performance for complex distributed automation systems. The IEC 61499 standard is designed to cover interoperability not only on the runtime level, but also during the design process. To migrate from IEC 61131-3 PLC to IEC 61499 function blocks, there are several approaches but only using ontology model can avoid manual translation during migration. This paper proposes a comprehensive ontology model for automation system, and an ontology example of airport baggage handling system is given. This is just a preliminary search results. An automatic semantic migration tool will be built based on the ontology model in the future.