In order to identify the unique critical thinking standards required by improvisational Q&A of English speaking, the author analyzed the responses of EFL speakers at different levels based on the universal critical thinking standards in the model proposed by Paul and Elder using a mixed method. It is found that there are significant differences in the mastery of critical thinking standards among the contestants, from high to low for all contestants being as follows: clarity of language, sufficiency of evidences, relevance of argumentation, and depth of viewpoints. High-level contestants perform significantly better than those low-level ones in these standards. In addition, this study also proposes corresponding improvement suggestions.