The purpose of vocational education is to teach students a skill while improving their cultural literacy. Engineering and technical personnel have rich practical experience, which is the channel for double-qualified teachers to obtain teacher qualification certificate after examination and enter the classroom to impart skills and knowledge. When college graduates teach in schools, they must practice in production, exercise, be familiar with production technology, master certain production skills, and return to the classroom to impart knowledge and skills, which is another channel for double-qualified teachers.