Today's science education emphasizes not only achievement in the cognitive domain but also achievement in the affective domain. In this study, the effect of Problem-Based Learning (PBL) on high school students' positive experiences about science in 'Life and Science' class was examined. For this purpose, the 'Wise Healthy Life' module developed by Kang et al. (2020) was applied for 19 classes to 68 third-year students from three classes who chose the subject 'Life and Science' at J high school in Jeollanam-do. This module applies PBL to solve topics related to everyday life such as disease, health, drugs, and food. Changes in high school students' positive experiences about science were investigated using the Test for Indicators of Positive Experiences about Science (TIPES) before and after 'Life and Science' class, and the causes of changes in students' positive experiences about science during the class were identified through survey and interview after class. As a result of the overall positive experiences about science test, the average scores of the pre-test and post-test were 2.93 and 3.17, and the students' positive experiences about science significantly improved after class. In the five sub-areas of positiv...