Abstract : This study aims to determine the effect of using scientific approach with discovery learning model of critical thinking skills and solving problems of fourth grade students of elementary school. This type of research is a quasi experiment with the pattern equivalent control group design. The subjects of the study were students of SD LAB UPI Campus Cibiru class IV-E (control / 26 students) and class IV-G (experiment / 26 students). Data collection are using the pretest-posttest technique. Data analysis used descriptive and inferential parametric statistics with SPSS 23.0 for windows program. The result of pretest thinking critically obtains t_count (0,099) <t_table (1,677), indicating the absence of difference of critical thinking of student. Posttest results of critical thinking earn t_count (2.591)> t_table (1.677), indicating there is a difference of students' critical thinking. The problem solving skill (pre test) earned t_count (0.087) < t_table (1.677), indicating no difference in problem solving skills. After being given treatment, problem solving skills (post test) obtain t_count (2.754)> t_table (1.677), indicating there are differences in student problem solving skills. Critical thinking skills and problem solving in the experimental class are higher than the control class. Based on data analysis, it is concluded that scientific approach with discovery learning model positively influence critical thinking skills and solve problems significantly.