This is an exploratory study to verify the impact of applying SNS to lecture on the professor trust and students achievement. The subject of the study is two groups which consist of SNS applied class and the group using legacy online class supporting system and the contents, material, activities of class are same. We verified the differences between two groups with the professor trust divided into 4 constructs such as intimacy, expertise, teaching ability, leadership based on the literature review and students achievement classified into midterm and final. The results shows that intimacy and final evaluation are statistically significant between two groups.