The present invention relates to novel crystalline forms of 7-cyclopentyl-2-(5-piperazin-1-yl-pyridin-2-ylamino)-7H-pyrrolo[2,3-d]pyrimidine-6-car boxylic acid dimethylamide(compound I), its salts, and process for preparation thereof. Crystalline forms in the present invention have good stability, low hygroscopicity, good processability, easy treatability and other favorable properties. In addition, the process is simple, low cost, and has an important value for future optimization and development of the drug.
