Cell-penetrating peptide (CPP) is a kind of small molecular peptide which can pass through a variety of cell membranes. It can carry bioactive macromolecules into cells. Due to lacking of tissue-selecting and targeting behavior, the application of CPP in the field of tumor treatment is limited. Activatable cell- penetrating peptide (ACPP) has brought the dawn to the application of CPP. This review mainly introduces the applications of ACPP in the targeting antitumor drug delivery which was designed based on the differences between tumor microenvironment and normal tissues as well as the exogenous physical stimulation.