Abstract: The present application belongs to the technical field of medicines, and specifically relates to a pharmaceutical composition for preventing and/or treating a cancer, in particular to a pharmaceutical composition containing a CDK4/6 inhibitor compound of Formula (I) or a pharmaceutically acceptable salt thereof in combination with a second therapeutic agent or a pharmaceutically acceptable salt thereof at a fixed ratio or a fixed dose, a use of the above pharmaceutical composition in preparation of a drug for preventing and/or treating a cancer, and a kit containing the pharmaceutical composition.