The study was carried out on 78 students majoring in tourism in a professional college based on their fourth-term final English achievements. A small scale questionnaire investigated students' English learning motivation. The study reveals that:1) Most of the professional college students English learning motivation is instrumental motivation or certificate motivation.2)Successful learners have intrinsic motivation.3)unsuccessfull earners have extrinsic motivation.4)Both successful learners and unsuccessful learners spend nearly the same time learning English. In the light of social constructivism,the thesis analyzes the students' English learning motivation in professional colleges on the basis of the result of the investigation. It also illustrates causes of formed motivation. Four education suggestions are put forward based on the study.