New crystal forms of palbociclib, and preparation method and use therefor

A plurality of new crystal forms I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII and XIV of 6-Acetyl-8-cyclopentyl-5-methyl-2-(5-piperazin-1-yl-pyridin-2-ylamino)-8H-pyrido[2,3-d]pyrimidin-7-one, as well as a preparation method and medicinal use therefor are disclosed in the present invention. Crystal form VIII is a semi-hydrate crystal form. Compared to crystal forms of the prior art, these new crystal forms are markedly superior in respect of dissolution, stability, and the preparation process.