This invention disclosed the substituted 2-hydropyrazol derivatives for selective CDK4/6 inhibitor. Particularly, this invention is about selective CDK4/6 inhibitor which represented by formula (I) or a pharmaceutically acceptable salt.本發明公開了作為選擇性的CDK4/6抑制劑取代的2-氫-吡唑衍生物。具體地講,本發明涉及作為選擇性的CDK4/6抑制劑的式(I)或其藥學上可接受的鹽。