This study purposes to figure out the effects of applying discussion-based science class on concept of science achievement and science teaching efficacy. This study established an twelve-week period of experimental treatment from April to June 2019, and the students who participated in this study formed a research group consisting of 27 students in the first semester of the second year of the B University of Education. and taking courses in ‘elementary Science Textbook Research 1’ For the classes applying discussion-based science class, the analysis was made on 2015 revised curriculum, and 12th process-centered performance assessment based on discussion. The developed data had designed to develop concept of science achievement and science teaching efficacy. The study group applied process-centered performance assessment based on discussion science class, so unaffectedly study group could improve their concept of science achievement and science teaching efficacy. B University of education is singleness class that doesn't have compare group, so this study is constituted only study group. Applying based-discussion science class to study group, before and after concept of science concept test, science teaching efficacy test is performed. The results of the study were as follows. First, the study group applied discussion-based science class had statistically significant differences in concept of science achievement (p<.05). Second, the study group applied discussion-based science class had statistically significant differences in science teaching efficacy(p<.05). Third, after discussion-based science class of pre-service teachers have a very good feeling. Through such study results, the study could figure out that the class applying discussion-based science class has positive effect on concept of science achievement and science teaching efficacy.