Provided are a crystalline form of a GnRH receptor antagonist and a preparation method therefor. Specifically, provided are a crystalline form I of 1-(4-(7-(2,6-difluorobenzyl)-3-((dimethylamino)methyl)-5-(6-methoxypyridazin-3-yl)-4 ,6-dicarbonyl-4,5,6,7-tetrahydro-2-pyrazolo[3,4-d]pyrimidin-2-yl)phenyl)-3-methoxy urea (a compound of formula I) and a preparation method, the use of same in a pharmaceutical composition and the use of the crystalline form I and the composition in the preparation of a drug for treating diseases associated with a GnRH receptor antagonist.
