This paper presents a detailed analysis of the effectiveness of a Project-based Approach conducted in an EAP writing class at Tsinghua University. The Project-based Approach means students propose and then conduct a survey based on [the/their] teacher's step-by-step guidance and group research. Different from previous studies where few has adopted a before-after contrast approach, our research is based on the correlation data yielded from two questionnaires completed by the students before and after the semester. Some of our important findings include students'approval of the Project-based Approach;the improvement of students'writing performance still lacking consistency;students'preference towards specific components of the Project-based Approach. These results support the hypothesis that the Project-based Approach is feasible and rewarding on the condition of Tsinghua University's teaching mode, and students'subjective perception towards this teaching method would benefit further teaching. One suggestion we would like to give to any further study of the same issue is that teaching results can be varied on account of different teaching methods and disparate teaching objects. Therefore, the effectiveness of the Project-based Approach of this research is only a guiding principle of comparable classes.