Generally, the learning process in classes still used worksheets that does not link the matter and instructional topics with local knowledge of local area. Though it is able to increase the students' conceptual understanding of the specific physics topics. This study aimed to analyze the practicality and effectiveness student' worksheet based on Ethno science in improving student understanding of rigid body' concept. The study used a quasi-experimental with pretest-post test control group design. The sample was students' senior high school in Lampung' province, Indonesia. The sampling technique used simple random sampling technique. Data were obtain through the questionnaire, responses of teachers and students, and test of learning outcome in multiple choice questions reasoned type. Data were analyzed by percentage, N-gain, and effect size. The results showed that student worksheet based on Ethno science was practically using in learning and effective in improving conceptual understanding which is indicated by the differences in test results between the control and the experimental class.