The present invention discloses a pharmaceutical composition comprising a pyridopyrimidine derivative or a pharmaceutically acceptable salt thereof. Specifically, the composition comprises 6-acetyl-8- cyclopentyl-5-methyl-2-{[5-(piperidin-4-yl)pyridin-2-yl]amino}pyrido[2,3-d]pyrimidin-7(8H)-one or a pharmacologically acceptable salt thereof, and a disintegrant. The disintegrant is a disintegrant with no metallic element. The composition dissolves rapidly. The preparation process of the pharmaceutical composition of the present invention is simple and more suitable for industrial-scale production.