In recent years, the Chinese proofreading technology has achieved good results at the word-level and the grammar-level, while it's relatively weak at the semantic level. This paper provides a new method of Chinese proofreading powered by the ontology technology. The semantic contents are firstly extracted from the Chinese texts and transformed into some kind of structured ontology, which is combined with the correct background ontology. The logical consistency of the extracted semantic content is determined by description logic reasoning machine, with the detected logical consistency error mapped into some Chinese semantic errors. This method is tested in the domain of political sensitive information. Compared with other methods, it has obvious advantages of the transparency of the semantic proofreading, the integrity of the semantic model and the intelligence of the semantic reasoning.