In this paper, we propose an ontology-based language, OntoEvent, for semantic complex event modeling and detection in Cyber-Physical Systems (CPS). We divide the core concepts of OntoEvent model into two levels: general concepts and domain-specific instances, to promise it can be dynamic extended for different CPS application domains. Complex events are modeled based on event ontology with logical and temporal operators, and these operators are extended by nature language synonymies. OntoEvent language is of rich expressiveness compared to other traditional languages. Based on OntoEvent, We propose an event detection model and elaborate its construction procedures. Experimental results prove that OntoEvent-based event detection model outperforms other selected models in processing efficiency, especially when processing multiple complex event ontologies.