Agomelatine crystal, which is a drug for treating depression, and pharmaceutical compositions thereof are provided. The X-ray powder diffraction spectra of such agomelatine crystal, which is irradiated by Cu-K± and showed by 20(degree), has characteristic diffraction peaks at 12.84, 13.84, 16.14, 18.56, 19.12, 20.86, 21.20, 23.84； its IR absorption pattern has characteristic absorption peaks at about 3234, 3060, 2940, 1638, 1511, 1436, 1249, 1215, 1184, 1032, 908, 828, 755, 588 cm-1； and its DSC endothermic transition temperature is 97.6°C. The use of the agomelatine crystal as an active ingredient in preparing a medicament for the treatment of depression is also provided.
