Abstract : In order to ensure a workflow to be executed correctly, many approaches were introduced. But not many of them consider the semantic correctness of the workflow in the design time and the run time. In this paper, a solution to check the semantic correctness of the workflow automatically is presented. To do that, the workflow must be represented in a machine understandable form, an ontology-based approach to represent a workflow is proposed. In addition, we also provide a set of changed operations allowing the users to customize a workflow for using in their organizations. Their change can be made while ensuring the correctness of the workflow. Moreover, a verification method is proposed for checking the semantic correctness of workflow.