The aim of this study was to analyze the understanding of students' concept on solar eclipse phenomena. The method of this study was a qualitative descriptive. This study was conducted for junior high school students at SMPN 21 Palu. The data were collected using multiple choice tests accompanied with Certain of Response Index (CRI) and interviews. The test was given before and after the solar eclipse occurred. This data was then calculated and analyzed to determine the percentage of understanding concept. Based on the analysis it can be concluded that students' understanding concept is in the medium category. A total solar eclipse phenomenon improves students' concepts. The study found misconceptions of the students in (1) position of the Sun, the Earth, and Moon during eclipse; (2) natural phenomena during solar eclipse; (3) phase of solar eclipse; and (4) safety methods on observing a solar eclipse.