The maintenance of OWL-S ontology syntactic consistency is very important in the evolution of semantic web services. In this paper, the differences between OWL-S and domain ontology are analyzed, and a maintenance framework is proposed to guide engineers to maintain the syntactic consistency of OWL-S. After the elementary changes of OWL-S are defined and abstracted, the change relation matrix is given to define the dependency between them, then, an algorithm to generate potential changes based on relation matrix is shown, and the time complexity of this algorithm is also analyzed. The syntactic consistency rules of OWL-S are divided into two types: mandate rules and optional rules while the descriptions and formal definitions of these rules are also given. In so doing, the agent can check these rules automatically, and help engineers to maintain the syntactic consistency of OWL-S ontology.