Due to complicated social lives, critical thinking is a critical capacity for people. The training of critical thinking is vital for teacher education students because they themselves will be teachers who can lead students to understand the complicated society. This study constructed a course design regarding critical thinking training based on critical thinking elements, consisting of ideological issues as instructional materials, blended learning with asynchronous dialogue as learning activities, and critical thinking quizzes as learning assessments. The above course was conducted for a semester, and the purpose of this study was to investigate teacher education students’ ability of critical thinking and to further identify the feasibility of the course design. A quasi-experimental design with a non-equivalent pre-test-post-test design was used to collect data about the rankings of the eight performances on critical thinking issues transformed from the content knowledge of the teacher education course for the experimental group and pre-test and post-test in critical thinking quizzes for the two groups. The experimental group contained 31 students, while the control group contained the other 35 students. This study concluded that the participants promoted their critical thinking ability through the integration of classroom delivery and asynchronous online communication. The course design of this study is feasible and recommended for teacher educators when considering the contents of ideological issues, the activities of blended learning, and the processes of teaching activities based on the transformation of critical thinking cognitive processes when designing a course regarding critical thinking.