Although questionnaire surveys are widely applied in second-language research, there is still little research on the application of questionnaire among early career researchers. Problems such as the lack of details concerning why the questionnaire survey is adopted, how the questionnaire is constructed, and how the survey is administered and reported are prevalent in student teachers’ research proposals or theses, which greatly impairs the quality of their academic work. However, few studies have been conducted to address these problems. This study aims to explore the real situation of the questionnaire survey application by examining student teachers’ perceptions of a questionnaire survey and their application of this research method to their theses. Using a mixed-method approach, the study collected quantitative and qualitative data from 138 student teachers, including 103 fresh undergraduates and 35 post-graduates. Quantitative data analysis used descriptive statistics, while qualitative data analysis used semi-structured interviews and content analysis. The study found that: (1) student teachers had some basic but unsystematic perceptions of the questionnaire survey. They had insufficient awareness of the rules of writing good questions, piloting questionnaires, sampling strategies, doing reliability, and validity analysis, etc. (2) Most student teachers developed questionnaires based on existing questionnaires without explaining reasons and adjustments. They introduced questionnaire design in their theses in an incomplete way, with piloting, selecting sample strategies, and statistical analysis methods often missing. Thus, some pedagogical implications can be drawn to improve student teachers’ awareness and competencies of the questionnaire survey.