It is human nature to desire to be close to Nature. Watching eco-films is a convenient way of satisfying this desire. It is also an approach for conducting environmental education. The National Museum of Natural Science has successfully introduced Wildscreen Festival awardwinning films to the public since 2012. Learning by audiences from watching and appreciating films is the focus of this study. The eco-film “Coral Garden” was used to develop an appreciation course. A questionnaire was designed to determine the level of satisfaction with this course among audience members. Data were analyzed using SPSS 12.0 and the results showed that audiences were highly satisfied with the course, especially with its rich content. Among four aspects, “increasing knowledge and understanding”, “increasing skills”, “transforming attitudes and values”, and “changing behaviors and actions”, the highest level of satisfaction was reported for “transforming attitudes and values”. The learning outcomes were analyzed using t-test. From the results, compared with males, females had higher level of satisfaction in terms of “willingness to protect marine resources”, “willingness to pay attention to human-ocean interactions”, “concern for other marine issues”, and “knowledge of the behaviors that damage coral”. From the results of ANOVA analysis, audience members aged 13 and above showed higher satisfaction in terms of “changing consumer behavior towards marine products” and “concern for other marine issues” than 4th-6th grade students. In conclusion, audiences showed significant changes in attitudes and values following an eco-film appreciation course. This is evidence of the positive efficacy of eco-film appreciation and corresponding guided session in environmental education.