Oral English teaching for Chinese postgraduates has always been focused on the drill of language skills， thus little attention was paid to the cultivation of students' thinking ability. This pa-per explored into the definition and theoretical basis of critical thinking and gave a case analysis of how to integrate the cultivation of critical thinking skills into the oral English classrooms in an effec-tive way. The questionnaire and interview among students showed that questioning， controversial dia-logue， debate and survey can help students to form the habit of critical thinking in an effective way and are also proved to be popular among medical postgraduates.