Abstract: In view of "absence of critical thinking" among students majoring in foreign languages in China, reforms in teaching materials, teaching methods and evaluation system have been launched in the Comprehensive English Course in our school in order to help undergraduate students develop their critical thinking abilities. With the hierarchical model of critical thinking as the theoretical framework, this study investigates the effects of these reforms on the development of the English majors' critical thinking abilities by combining the pretest-post-test with the control-experiment design. A questionnaire is used to measure the dispositional dimension and the use of cognitive skills, while a writing test is used to measure cognitive standards. In what ways the reforms are effective and in what ways they are still lacking are discussed and suggestions are given to improve the teaching of undergraduate courses of foreign languages.