The theory of spatial thinking is relevant to the learning and teaching of many academic domains. One promising method to facilitate learners' higher-order thinking is to utilize a web map mind tool to assist learners in applying spatial thinking to cooperative problem solving. In this study, an environment is designed based on the theory of spatial thinking and developed to help learners engage in project-based learning that utilizes the proposed web map mind tool for tour planning. The participants were 66 college students, and a quasi-experimental research design was employed. This study examined the differences in the learning performance and project performance between participants using the web map mind tool (the experimental group) and ordinary Internet search engines (the control group). The results indicate the experimental group performed significantly better than the control group in terms of both learning performance and project performance. In addition, we found that the students in the two groups held a positive learning attitude toward the project activity of tour planning. In terms of students' attitude toward the use of a mind tool, this study only conducted a survey for the experimental group. The results indicated that learners in the experimental group held a positive attitude toward the use of the web map mind tool.