This study aimed to describe the mathematical communication skills of the seventh grade students in MA (islamic Senor High) Ma'arif NU 2 Ajibarang on Algebra. This research includes qualitatived method with analytical techniques which covers data reduction, data presentation, and conclusions. The data collection was conducted trough a test, interviews and documentation. The subject of the research was taken using purposive sampling technique. Tringulation technique was used in the validation test. The results of this study showed that students in high achievement grup have good mathematical communication skill, students in average achievement group have good cummunication skill, and students in low achievement group have poor communication