Abstract: Critical discourse analysis takes a social and cultural perspective to study the language and discourse in specific social context，as well as the social background in which the discourse takes place. It pays attention to social problems，taking social，cultural practices and structure as the starting point to study the language. Historical discourse analysis is one method of critical discourse analysis，which connects random historical incidents with linguistic analysis，hence more accurate analysis of the context knitted with social ideologies and rights are achieved. Comparison of published news before and after specific historical stage provides a foundation for exploring the changes in society and ideology.

Key words: critical discourse analysis, social ideology, diachronic corpus, SinoAmerican relations