Assessment of students’ learning outcomes is one of the important components of the teaching process in general and capacity development teaching in particular. To assess students’ ability, teachers must use a combination of many different assessment methods and tools, in which Rubric is considered an assessment tool with many advantages. The article analyzes some problems about Rubric and the relationship between using Rubric in teaching Natural and Social subjects in primary school to assess students’ ability. From there, this study proposes a process and builds a specific example on a lesson of the 3rd grade Nature and Society subject, in order to help teachers better understand Rubric and be able to apply it to design Rubric suitable for them.