This research examines the effect of a natural approach using animation video as a media in improving students’ vocabulary mastery. The sample of this study was all eighth grade students of SMP N 1 Tahunan. The researcher took class VIII F as an experimental group and Class VIII E as a control group. In data collection, the researcher uses pre-test, treatment, and post-test in each group. The experimental and control group did pre-test. The experimental group received treatment of Natural Approach using Animation Video while control group was treated by Think Pair Share. Then, a post-test was done for each group. The results were analyzed through ANOVA. The result shows that there was effectiveness between Natural Approach using Animation Video. Students got good score after being taught Natural Approach using Animation Video compared to using Think Pair Share. Besides that in the experimental class average score was 87.87 on the other hand in control class was 83.06. It can be seen from Tvalue > Ttable (4,860 > 3,32). Ho was rejected and Ha was accepted. Finally, this research can be useful information or can be used as a reference for other researchers who are interested in doing similar research.