Peptidyl-prolyl cis/trans isomerase family (PPIase) is structurally divided into three subfamilies, cyclophilins (Cyps), FK506-binding proteins (FKBPs), and parvulins. Pin1 belongs to the parvulin family and is the only enzyme capable of isomerizing the phosphorylated Ser/Thr-Pro motif (p-Ser/Thr-Pro) in its interacting proteins. Due to its multibiological functions in vivo, including folding, intracellular signaling, transcription, cell cycle progression, and apoptosis, Pin1 is extensively studied as a promising drug target for various human diseases, especially cancer. In this Perspective, we summarized the literature covering diverse classes of Pin1 inhibitors and the inhibition mechanism, aiming to provide insights for the design of potent Pin1 inhibitors and suggest alternative strategies for developing potent Pin1 inhibitors.