The national policy for bilingual education was declared in 2017 in Taiwan. Since then, Taiwan has been on the way to becoming a bilingual nation by 2030. Relevant plans, workshops, and immersion teaching activities have been proposed and challenged teachers in Taiwan. Based on such outcomes, we investigate students’ attitudes toward bilingual programs and the importance of code-switching and mixing in teaching. The data analysis and findings indicate that 1) students’ English proficiency does not affect their attitudes toward the bilingual program, 2) there are no gender differences in the attitudes toward the bilingual program, 3) teachers usually code-switch and mix when asking students questions, explaining the steps and main ideas, and repeating the instructions or descriptions, and 4) the code-switching and mixing are essential when students learn the course content in the bilingual class. According to such findings, teachers can supplement their bilingual teaching. Besides, foreign teachers are considerably helpful in building a proper bilingual learning environment. With them, students participate in language learning more actively. This study result can be a reference for educational administrations for their planning.