The snack food of schoolchildren (PJAS) is a snack found in school wards and is a daily consumed schoolboy, consisting of drinks, fruits, snacks, and snacks for children during recess and after school. The purpose of this study is to know the level of students' knowledge and attitude about the snack before the application and after the application of school child snack food. The study used experimental methods, the research that gave intervention to the sample studied with the design of One - Group Pretest - Posttest Design. The design uses one group of respondents as a sample to pretest and posttest. Research samples taken by the method of stratified random samples were obtained with a total of 40 samples. The locus is Madrasah Ibtidaiyah Chairul Bariyah Sei Semayang Village. Studies indicate that there is a difference in knowledge and students' attitudes about the food children's snacks before and after education is offered. All respondents (100%) had a good knowledge of and attitude after they were given an education about the welfare of schoolchildren. In conclusion, students have a good knowledge and attitude about a child's snack after tutoring. It is recommended to school authorities adopt a child's healthy snack policy and school performance.