With a rapid pace of urbanization, urban environment problems have affected large numbers of people and aroused widespread concern. Landscape architecture design helps improve the welfare of urban residents and ecological function of urban green spaces. Course-based influence of college students majoring in landscape architecture is an efficient way to prepare future landscape architects with environmental awareness. This research applied project-based learning (PBL) and zone of proximal development (ZPD) in the landscape architecture design course, and developed the investigation–design–construction PBL modules of the course. The experimental group, 57 college juniors majoring in landscape architecture, received PBL education while learning the course. At the end of the course, a questionnaire was answered by the junior students and the control group, which comprised 60 senior students who received no PBL instruction while learning the same course in the third year. The results indicate that the PBL approach was well accepted by 90% of the experimental group, who were 17.37% more likely to employ pro-environmental design methods in their future work than the control group. It was also found that employing the PBL approach in the landscape architecture design course had a positive influence upon students’ pro-environmental values, knowledge and attitudes.